2017-04-05 01:48:34 +03:00
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< h1 > Utilities< a class = "headerlink" href = "#utilities" title = "Permalink to this headline" > ¶< / a > < / h1 >
< p > The utility functions exposed in both the < em > ethers< / em > umbrella package and the < em > ethers-utils< / em > :< / p >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > var< / span > < span class = "n" > utils< / span > < span class = "o" > =< / span > < span class = "n" > ethers< / span > < span class = "o" > .< / span > < span class = "n" > utils< / span > < span class = "p" > ;< / span >
< / pre > < / div >
< / div >
< hr class = "docutils" / >
< div class = "section" id = "big-numbers" >
< span id = "bignumber" > < / span > < h2 > Big Numbers< a class = "headerlink" href = "#big-numbers" title = "Permalink to this headline" > ¶< / a > < / h2 >
< p > A BigNumber is an immutable object which allow math operations to be carried
out on numbers far larger than < a class = "reference internal" href = "notes.html#ieee754" > < span class = "std std-ref" > JavaScript can accurately handle< / span > < / a > .
Many functions return these, so it is important to understand how to work with these.< / p >
< dl class = "docutils" >
< dt > < sup > prototype< / sup > . add ( otherValue )< / dt >
< dd > Return a new BigNumber of this plus < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . sub ( otherValue )< / dt >
< dd > Return a new BigNumber of this minus < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . mul ( otherValue )< / dt >
< dd > Return a new BigNumber of this times < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . div ( otherValue )< / dt >
< dd > Return a new BigNumber of this divided by < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . mod ( otherValue )< / dt >
< dd > Return a new BigNumber of this modulo < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . eq ( otherValue )< / dt >
< dd > Return true if this is equal to < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . lt ( otherValue )< / dt >
< dd > Return true if this is less than < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . lte ( otherValue )< / dt >
< dd > Return true if this is less or equal to < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . gt ( otherValue )< / dt >
< dd > Return true if this is greater than < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . gte ( otherValue )< / dt >
< dd > Return true if this is greater than or equal to < em > otherValue< / em > < / dd >
< dt > < sup > prototype< / sup > . isZero ( )< / dt >
< dd > Return true if this is equal to zero< / dd >
< dt > < sup > prototype< / sup > . toNumber ( )< / dt >
< dd > Return a JavaScript number representation; an error is thrown if the value is
outside the safe range for JavaScript IEEE 754 64-bit floating point numbers< / dd >
< dt > < sup > prototype< / sup > . toString ()< / dt >
< dd > Return a decimal string representation< / dd >
< dt > < sup > prototype< / sup > . toHexString ( )< / dt >
< dd > Return a < strong > 0x prefixed< / strong > hexidecimal representation< / dd >
< / dl >
< div class = "section" id = "creating-instances" >
< h3 > Creating Instances< a class = "headerlink" href = "#creating-instances" title = "Permalink to this headline" > ¶< / a > < / h3 >
< dl class = "docutils" >
< dt > < sup > utils< / sup > < strong > . bigNumberify< / strong > ( value )< / dt >
< dd > < p class = "first" > Returns a BigNumber instance of < em > value< / em > . The < em > value< / em > may be anything which can be
reliably converted into a BigNumber:< / p >
< dl class = "last docutils" >
< dt > < em > Decimal String< / em > < / dt >
< dd > < p class = "first" > A string consisting of the decimal digits 0 through 9, optionally with a leading
negative sign.< / p >
< p class = "last" > < strong > examples:< / strong > utils.bigNumberify(“ 42” )< / p >
< / dd >
< dt > < em > Hex String< / em > < / dt >
< dd > < p class = "first" > A < a class = "reference internal" href = "#hexstring" > < span class = "std std-ref" > hex string< / span > < / a > , witch has aa < strong > prefix of 0x< / strong > and consisting
of the hexidecimal digits 0 through 9 and a through f, case-insensitive. Must
be non-negative.< / p >
< p class = "last" > < strong > examples:< / strong > utils.bigNumberify(“ 0x2a” )< / p >
< / dd >
< dt > < em > JavaScript Numbers< / em > < / dt >
< dd > < p class = "first" > Numbers must be within the < a class = "reference external" href = "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isSafeInteger" > safe range< / a > for JavaScript.< / p >
< p class = "last" > < strong > examples:< / strong > utils.bigNumberify(42)< / p >
< / dd >
< dt > < em > Arrayish< / em > < / dt >
< dd > < p class = "first" > Treats the < a class = "reference internal" href = "#api-arrayish" > < span class = "std std-ref" > arrayish< / span > < / a > as a big-endian encoded bytes representation.< / p >
< p class = "last" > < strong > examples:< / strong > utils.bigNumberify([ 42 ])< / p >
< / dd >
< dt > < em > BigNumber< / em > < / dt >
< dd > Returns < em > value< / em > , since a BigNumber is immutable.< / dd >
< / dl >
< / dd >
< / dl >
< / div >
< div class = "section" id = "examples" >
< h3 > < em > Examples< / em > < a class = "headerlink" href = "#examples" title = "Permalink to this headline" > ¶< / a > < / h3 >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > var< / span > < span class = "n" > gasPriceWei< / span > < span class = "o" > =< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > bigNumberify< / span > < span class = "p" > (< / span > < span class = "s2" > " 20902747399" < / span > < span class = "p" > );< / span >
< span class = "n" > var< / span > < span class = "n" > gasLimit< / span > < span class = "o" > =< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > bigNumberify< / span > < span class = "p" > (< / span > < span class = "mi" > 3000000< / span > < span class = "p" > );< / span >
< span class = "n" > var< / span > < span class = "n" > maxCostWei< / span > < span class = "o" > =< / span > < span class = "n" > gasPriceWei< / span > < span class = "o" > .< / span > < span class = "n" > mul< / span > < span class = "p" > (< / span > < span class = "n" > gasLimit< / span > < span class = "p" > )< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "s2" > " Max Cost: " < / span > < span class = "o" > +< / span > < span class = "n" > maxCostWei< / span > < span class = "o" > .< / span > < span class = "n" > toString< / span > < span class = "p" > ());< / span >
< span class = "o" > //< / span > < span class = "s2" > " Max Cost: 62708242197000000" < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "s2" > " Number: " < / span > < span class = "o" > +< / span > < span class = "n" > maxCostWei< / span > < span class = "o" > .< / span > < span class = "n" > toNumber< / span > < span class = "p" > ());< / span >
< span class = "o" > //< / span > < span class = "n" > throws< / span > < span class = "n" > an< / span > < span class = "n" > Error< / span > < span class = "p" > ,< / span > < span class = "n" > the< / span > < span class = "n" > value< / span > < span class = "ow" > is< / span > < span class = "n" > too< / span > < span class = "n" > large< / span > < span class = "k" > for< / span > < span class = "n" > JavaScript< / span > < span class = "n" > to< / span > < span class = "n" > handle< / span > < span class = "n" > safely< / span >
< / pre > < / div >
< / div >
< / div >
< / div >
< hr class = "docutils" / >
< div class = "section" id = "ether-strings-and-wei" >
< h2 > Ether Strings and Wei< a class = "headerlink" href = "#ether-strings-and-wei" title = "Permalink to this headline" > ¶< / a > < / h2 >
< dl class = "docutils" >
< dt > < sup > utils< / sup > . etherSymbol< / dt >
< dd > The ethereum symbol (the Greek letter < em > Xi< / em > )< / dd >
< / dl >
< dl class = "docutils" id = "parseether" >
< dt > < sup > utils< / sup > . parseEther ( etherString )< / dt >
< dd > Parse the < em > etherString< / em > representation of ether into a BigNumber instance
of the amount of wei.< / dd >
< / dl >
< dl class = "docutils" id = "formatether" >
< dt > < sup > utils< / sup > . formatEther ( wei [ , options ] )< / dt >
< dd > Format an amount of < em > wei< / em > into a decimal string representing the amount of ether. The
< em > options< / em > object supports the keys < code class = "docutils literal" > < span class = "pre" > commify< / span > < / code > and < code class = "docutils literal" > < span class = "pre" > pad< / span > < / code > . The output will always
include at least one whole number and at least one decimal place.< / dd >
< / dl >
< div class = "section" id = "id1" >
< h3 > < em > Examples< / em > < a class = "headerlink" href = "#id1" title = "Permalink to this headline" > ¶< / a > < / h3 >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > var< / span > < span class = "n" > wei< / span > < span class = "o" > =< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > parseEther< / span > < span class = "p" > (< / span > < span class = "s1" > ' 1000.0' < / span > < span class = "p" > );< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > wei< / span > < span class = "o" > .< / span > < span class = "n" > toString< / span > < span class = "p" > (< / span > < span class = "mi" > 10< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 1000000000000000000000" < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > formatEther< / span > < span class = "p" > (< / span > < span class = "mi" > 0< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 0.0" < / span >
< span class = "n" > var< / span > < span class = "n" > wei< / span > < span class = "o" > =< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > bigNumberify< / span > < span class = "p" > (< / span > < span class = "s2" > " 1000000000000000000000" < / span > < span class = "p" > );< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > formatEther< / span > < span class = "p" > (< / span > < span class = "n" > wei< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 1000.0" < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > formatEther< / span > < span class = "p" > (< / span > < span class = "n" > wei< / span > < span class = "p" > ,< / span > < span class = "p" > {< / span > < span class = "n" > commify< / span > < span class = "p" > :< / span > < span class = "n" > true< / span > < span class = "p" > }));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 1,000.0" < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > formatEther< / span > < span class = "p" > (< / span > < span class = "n" > wei< / span > < span class = "p" > ,< / span > < span class = "p" > {< / span > < span class = "n" > pad< / span > < span class = "p" > :< / span > < span class = "n" > true< / span > < span class = "p" > }));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 1000.000000000000000000" < / span > < span class = "p" > (< / span > < span class = "mi" > 18< / span > < span class = "n" > decimal< / span > < span class = "n" > places< / span > < span class = "p" > )< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > formatEther< / span > < span class = "p" > (< / span > < span class = "n" > wei< / span > < span class = "p" > ,< / span > < span class = "p" > {< / span > < span class = "n" > commify< / span > < span class = "p" > :< / span > < span class = "n" > true< / span > < span class = "p" > ,< / span > < span class = "n" > pad< / span > < span class = "p" > :< / span > < span class = "n" > true< / span > < span class = "p" > }));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 1,000.000000000000000000" < / span > < span class = "p" > (< / span > < span class = "mi" > 18< / span > < span class = "n" > decimal< / span > < span class = "n" > places< / span > < span class = "p" > )< / span >
< / pre > < / div >
< / div >
< / div >
< / div >
< hr class = "docutils" / >
< div class = "section" id = "addresses" >
< h2 > Addresses< a class = "headerlink" href = "#addresses" title = "Permalink to this headline" > ¶< / a > < / h2 >
< p > There are < a class = "reference internal" href = "notes.html#checksum-address" > < span class = "std std-ref" > several formats< / span > < / a > available on the Ethereum network for
addresses, and it is often useful to be able to convert between them.< / p >
< dl class = "docutils" id = "api-getaddress" >
< dt > < sup > utils< / sup > . getAddress ( address [ , generateIcap ] )< / dt >
< dd > Normalize an address to a < a class = "reference internal" href = "notes.html#checksum-address" > < span class = "std std-ref" > checksum address< / span > < / a > , or as an
< a class = "reference internal" href = "notes.html#icap-address" > < span class = "std std-ref" > ICAP< / span > < / a > address if < em > generateIcap< / em > is true.< / dd >
< / dl >
< div class = "section" id = "id2" >
< h3 > < em > Examples< / em > < a class = "headerlink" href = "#id2" title = "Permalink to this headline" > ¶< / a > < / h3 >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > var< / span > < span class = "n" > address< / span > < span class = "o" > =< / span > < span class = "s2" > " 0xd115bffabbdd893a6f7cea402e7338643ced44a6" < / span > < span class = "p" > ;< / span >
< span class = "n" > var< / span > < span class = "n" > icapAddress< / span > < span class = "o" > =< / span > < span class = "s2" > " XE93OF8SR0OWI6F4FO88KWO4UNNGG1FEBHI" < / span > < span class = "p" > ;< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "s1" > ' Checksum address: ' < / span > < span class = "o" > +< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > getAddress< / span > < span class = "p" > (< / span > < span class = "n" > address< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 0xD115BFFAbbdd893A6f7ceA402e7338643Ced44a6" < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "s1" > ' Checksum address: ' < / span > < span class = "o" > +< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > getAddress< / span > < span class = "p" > (< / span > < span class = "n" > icapAddress< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 0xD115BFFAbbdd893A6f7ceA402e7338643Ced44a6" < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "s1" > ' ICAP address:' < / span > < span class = "o" > +< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > getAddress< / span > < span class = "p" > (< / span > < span class = "n" > address< / span > < span class = "p" > ,< / span > < span class = "n" > true< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " XE93OF8SR0OWI6F4FO88KWO4UNNGG1FEBHI" < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "s1" > ' ICAP address:' < / span > < span class = "o" > +< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > getAddress< / span > < span class = "p" > (< / span > < span class = "n" > icapAddress< / span > < span class = "p" > ,< / span > < span class = "n" > true< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " XE93OF8SR0OWI6F4FO88KWO4UNNGG1FEBHI" < / span >
< / pre > < / div >
< / div >
< / div >
< / div >
< hr class = "docutils" / >
< div class = "section" id = "utf-8-strings" >
< h2 > UTF-8 Strings< a class = "headerlink" href = "#utf-8-strings" title = "Permalink to this headline" > ¶< / a > < / h2 >
< dl class = "docutils" >
< dt > < sup > utils< / sup > . toUtf8Bytes ( string )< / dt >
< dd > Converts a UTF-8 string to a Uint8Array.< / dd >
< dt > < sup > utils< / sup > . toUtf8String ( hexStringOrArrayish )< / dt >
< dd > Converts a hex-encoded string or array to its UTF-8 representation.< / dd >
< / dl >
< div class = "section" id = "id3" >
< h3 > < em > Examples< / em > < a class = "headerlink" href = "#id3" title = "Permalink to this headline" > ¶< / a > < / h3 >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > var< / span > < span class = "n" > text< / span > < span class = "o" > =< / span > < span class = "s2" > " Hello World" < / span > < span class = "p" > ;< / span >
< span class = "n" > var< / span > < span class = "nb" > bytes< / span > < span class = "o" > =< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > toUtf8Bytes< / span > < span class = "p" > (< / span > < span class = "n" > text< / span > < span class = "p" > );< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "nb" > bytes< / span > < span class = "p" > );< / span >
< span class = "o" > //< / span > < span class = "n" > Uint8Array< / span > < span class = "p" > [< / span > < span class = "mi" > 72< / span > < span class = "p" > ,< / span > < span class = "mi" > 101< / span > < span class = "p" > ,< / span > < span class = "mi" > 108< / span > < span class = "p" > ,< / span > < span class = "mi" > 108< / span > < span class = "p" > ,< / span > < span class = "mi" > 111< / span > < span class = "p" > ,< / span > < span class = "mi" > 32< / span > < span class = "p" > ,< / span > < span class = "mi" > 87< / span > < span class = "p" > ,< / span > < span class = "mi" > 111< / span > < span class = "p" > ,< / span > < span class = "mi" > 114< / span > < span class = "p" > ,< / span > < span class = "mi" > 108< / span > < span class = "p" > ,< / span > < span class = "mi" > 100< / span > < span class = "p" > ]< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > toUtf8String< / span > < span class = "p" > (< / span > < span class = "nb" > bytes< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " Hello World" < / span >
< span class = "n" > var< / span > < span class = "n" > hexString< / span > < span class = "o" > =< / span > < span class = "s2" > " 0x48656c6c6f20576f726c64" < / span > < span class = "p" > ;< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > toUtf8String< / span > < span class = "p" > (< / span > < span class = "n" > hexString< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " Hello World" < / span >
< / pre > < / div >
< / div >
< / div >
< / div >
< hr class = "docutils" / >
< div class = "section" id = "cryptographic-functions" >
< h2 > Cryptographic Functions< a class = "headerlink" href = "#cryptographic-functions" title = "Permalink to this headline" > ¶< / a > < / h2 >
< dl class = "docutils" >
< dt > < sup > utils< / sup > . keccak256 ( hexStringOrArrayish )< / dt >
< dd > Compute the keccak256 cryptographic hash of a value, returned as a hex string. (Note:
often Ethereum refers to this, < strong > incorrectly< / strong > , as SHA3)< / dd >
< dt > < sup > utils< / sup > . sha256 ( hexStringOrArrayish )< / dt >
< dd > Compute the SHA2-256 cryptographic hash of a value, returned as a hex string.< / dd >
< dt > < sup > utils< / sup > . randomBytes ( length )< / dt >
< dd > Return a Uint8Array of cryptographically secure random bytes< / dd >
< / dl >
< div class = "section" id = "id4" >
< h3 > < em > Examples< / em > < a class = "headerlink" href = "#id4" title = "Permalink to this headline" > ¶< / a > < / h3 >
< p > < strong > Hashing Binary Data< / strong > < / p >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > keccak256< / span > < span class = "p" > ([< / span > < span class = "mh" > 0x42< / span > < span class = "p" > ]));< / span >
< span class = "o" > //< / span > < span class = "s1" > ' 0x1f675bff07515f5df96737194ea945c36c41e7b4fcef307b7cd4d0e602a69111' < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > keccak256< / span > < span class = "p" > (< / span > < span class = "s2" > " 0x42" < / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s1" > ' 0x1f675bff07515f5df96737194ea945c36c41e7b4fcef307b7cd4d0e602a69111' < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > sha256< / span > < span class = "p" > ([< / span > < span class = "mh" > 0x42< / span > < span class = "p" > ]));< / span >
< span class = "o" > //< / span > < span class = "s1" > ' 0xdf7e70e5021544f4834bbee64a9e3789febc4be81470df629cad6ddb03320a5c' < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > sha256< / span > < span class = "p" > (< / span > < span class = "s2" > " 0x42" < / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s1" > ' 0xdf7e70e5021544f4834bbee64a9e3789febc4be81470df629cad6ddb03320a5c' < / span >
< / pre > < / div >
< / div >
< p > < strong > Hashing UTF-8 Strings< / strong > < / p >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "o" > //< / span > < span class = "n" > Convert< / span > < span class = "n" > the< / span > < span class = "n" > string< / span > < span class = "n" > to< / span > < span class = "n" > binary< / span > < span class = "n" > data< / span >
< span class = "n" > var< / span > < span class = "n" > utf8Bytes< / span > < span class = "o" > =< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > toUtf8Bytes< / span > < span class = "p" > (< / span > < span class = "s1" > ' Hello World' < / span > < span class = "p" > );< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > keccak256< / span > < span class = "p" > (< / span > < span class = "n" > utf8Bytes< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s1" > ' 0x592fa743889fc7f92ac2a37bb1f5ba1daf2a5c84741ca0e0061d243a2e6707ba' < / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > sha256< / span > < span class = "p" > (< / span > < span class = "n" > utf8Bytes< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s1" > ' 0xa591a6d40bf420404a011733cfb7b190d62c65bf0bcda32b57b277d9ad9f146e' < / span >
< / pre > < / div >
< / div >
< p > < strong > Random Bytes< / strong > < / p >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > randomBytes< / span > < span class = "p" > (< / span > < span class = "mi" > 3< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "n" > Uint8Array< / span > < span class = "p" > [< / span > < span class = "mi" > 194< / span > < span class = "p" > ,< / span > < span class = "mi" > 22< / span > < span class = "p" > ,< / span > < span class = "mi" > 140< / span > < span class = "p" > ]< / span >
< / pre > < / div >
< / div >
< hr class = "docutils" / >
< / div >
< / div >
< div class = "section" id = "arrayish" >
< span id = "api-arrayish" > < / span > < h2 > Arrayish< a class = "headerlink" href = "#arrayish" title = "Permalink to this headline" > ¶< / a > < / h2 >
< p > An arrayish object is any such that it:< / p >
< ul class = "simple" >
< li > has a < em > length< / em > property< / li >
< li > has a value for each index from 0 up to (but excluding) < em > length< / em > < / li >
< li > has a valid byte for each value; a byte is an integer in the range [0, 255]< / li >
< / ul >
< dl class = "docutils" >
< dt > < sup > utils< / sup > . isArrayish ( object )< / dt >
< dd > Returns true if < em > object< / em > can be treated as an arrayish object.< / dd >
< dt > < sup > utils< / sup > . arrayify ( hexStringOrArrayish )< / dt >
< dd > Returns a Uint8Array of a hex string, BigNumber or of an < a class = "reference internal" href = "#arrayish" > Arrayish< / a > object.< / dd >
< dt > < sup > utils< / sup > . concat ( arrayOfHexStringsAndArrayish )< / dt >
< dd > Return a Uint8Array of all < em > arrayOfHexStringsAndArrayish< / em > concatenated.< / dd >
< dt > < sup > utils< / sup > . padZeros ( typedUint8Array, length )< / dt >
< dd > Return a Uint8Array of < em > typedUint8Array< / em > with zeros prepended to < em > length< / em > bytes.< / dd >
< dt > < sup > utils< / sup > . stripZeros ( hexStringOrArrayish )< / dt >
< dd > Returns a Uint8Array with all leading zero < strong > bytes< / strong > striped.< / dd >
< / dl >
< hr class = "docutils" / >
< / div >
< div class = "section" id = "hex-strings" >
< span id = "hexstring" > < / span > < h2 > Hex Strings< a class = "headerlink" href = "#hex-strings" title = "Permalink to this headline" > ¶< / a > < / h2 >
< p > A hex string is < strong > always< / strong > prefixed with “ 0x” and consists of the characters
0 – 9 and a – f. It is always returned lower case with even-length, but any hex
string passed into a function may be any case and may be odd-length.< / p >
< dl class = "docutils" >
< dt > < sup > utils< / sup > . hexlify ( numberOrBigNumberOrHexStringOrArrayish )< / dt >
< dd > Converts any number, < a class = "reference internal" href = "#bignumber" > < span class = "std std-ref" > BigNumber< / span > < / a > , hex string or
< a class = "reference internal" href = "#arrayish" > Arrayish< / a > to a hex string. (otherwise, throws an error)< / dd >
< / dl >
< / div >
< hr class = "docutils" / >
< div class = "section" id = "contract-addresses" >
< h2 > Contract Addresses< a class = "headerlink" href = "#contract-addresses" title = "Permalink to this headline" > ¶< / a > < / h2 >
< p > Every contract deployed on the Ethereum network requires an address (you can think
of this as the memory address which the running application lives at). The address
is generated from a cryptographic has of the address of the creator and the nonce
of the transaction.< / p >
< dl class = "docutils" >
< dt > < sup > utils< / sup > . getContractAddress ( transaction )< / dt >
< dd > Computes the contract address a contract would have if this transaction
created a contract. (transaction requires only < code class = "docutils literal" > < span class = "pre" > from< / span > < / code > and < code class = "docutils literal" > < span class = "pre" > nonce< / span > < / code > be
defined)< / dd >
< / dl >
< div class = "section" id = "id5" >
< h3 > < em > Examples< / em > < a class = "headerlink" href = "#id5" title = "Permalink to this headline" > ¶< / a > < / h3 >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "o" > //< / span > < span class = "n" > Ropsten< / span > < span class = "p" > :< / span > < span class = "mh" > 0x5bdfd14fcc917abc2f02a30721d152a6f147f09e8cbaad4e0d5405d646c5c3e1< / span >
< span class = "n" > var< / span > < span class = "n" > transaction< / span > < span class = "o" > =< / span > < span class = "p" > {< / span >
< span class = "n" > from< / span > < span class = "p" > :< / span > < span class = "s1" > ' 0xc6af6e1a78a6752c7f8cd63877eb789a2adb776c' < / span > < span class = "p" > ,< / span >
< span class = "n" > nonce< / span > < span class = "p" > :< / span > < span class = "mi" > 0< / span >
< span class = "p" > };< / span >
< span class = "n" > console< / span > < span class = "o" > .< / span > < span class = "n" > log< / span > < span class = "p" > (< / span > < span class = "n" > utils< / span > < span class = "o" > .< / span > < span class = "n" > getContractAddress< / span > < span class = "p" > (< / span > < span class = "n" > transaction< / span > < span class = "p" > ));< / span >
< span class = "o" > //< / span > < span class = "s2" > " 0x0CcCC7507aEDf9FEaF8C8D731421746e16b4d39D" < / span >
< / pre > < / div >
< / div >
< hr class = "docutils" / >
< / div >
< / div >
< / div >
< / div >
< / div >
< footer >
< div class = "rst-footer-buttons" role = "navigation" aria-label = "footer navigation" >
< a href = "api-advanced.html" class = "btn btn-neutral float-right" title = "Low-Level API" accesskey = "n" > Next < span class = "fa fa-arrow-circle-right" > < / span > < / a >
< a href = "api-contract.html" class = "btn btn-neutral" title = "Contracts" accesskey = "p" > < span class = "fa fa-arrow-circle-left" > < / span > Previous< / a >
< / div >
< hr / >
< div role = "contentinfo" >
< p >
© Copyright 2016, Richard Moore < me@ricmoo.com> .
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Built with < a href = "http://sphinx-doc.org/" > Sphinx< / a > using a < a href = "https://github.com/snide/sphinx_rtd_theme" > theme< / a > provided by < a href = "https://readthedocs.org" > Read the Docs< / a > .
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