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<html><head><title>Strings</title><link rel="stylesheet" type="text/css" href="/static/style.css"></head><body><div class="sidebar"><div class="header"><div class="logo"><a href="/"><div class="image"></div><div class="name">ethers.js</div><div class="version">v5.0</div></a></div></div><div class="toc"><div><div class="link title"><a href="/">Documentation</a></div><div class="base show link depth-1"><a href="/getting-started/">Getting Started</a></div><div class="hide link depth-2"><a href="/getting-started/#installing">Installing</a></div><div class="hide link depth-2"><a href="/getting-started/#importing">Importing</a></div><div class="base show link depth-1"><a href="/concepts/">Concepts</a></div><div class="hide link depth-2"><a href="/concepts/events/">Events</a></div><div class="hide link depth-2"><a href="/concepts/gas/">Gas</a></div><div class="hide link depth-3"><a href="/concepts/gas/#gas-price">Gas Price</a></div><div class="hide link depth-3"><a href="/concepts/gas/#gas-limit">Gas Limit</a></div><div class="base ancestor show link depth-1"><a href="/api/">Application Programming Interface</a></div><div class="show link depth-2"><a href="/api/contract/">Contracts</a></div><div class="hide link depth-3"><a href="/api/contract/#buckets">Buckets</a></div><div class="show link depth-2"><a href="/api/signer/">Signers</a></div><div class="hide link depth-3"><a href="/api/signer/#signer">Signer</a></div><div class="hide link depth-3"><a href="/api/signer/#wallet-inherits-signer">Wallet inherits Signer</a></div><div class="show link depth-2"><a href="/api/providers/">Providers</a></div><div class="hide link depth-3"><a href="/api/providers/provider/">Provider</a></div><div class="hide link depth-4"><a href="/api/providers/provider/#accounts-methods">Accounts Methods</a></div><div class="hide link depth-4"><a href="/api/providers/provider/#blocks-methods">Blocks Methods</a></div><div class="hide link depth-4"><a href="/api/providers/provider/#ethereum-naming-service-(ens)-methods">Ethereum Naming Service (ENS) Methods</a></div><div class="hide link depth-4"><a href="/api/providers/provider/#logs-methods">Logs Methods</a></div><div class="hide link depth-4"><a href="/api/providers/provider/#network-status-methods">Network Status Methods</a></div><div class="hide link depth-4"><a href="/api/providers/provider/#transactions-methods">Transactions Methods</a></div><div class="hide link depth-4"><a href="/api/providers/provider/#event-emitter-methods">Event Emitter Methods</a></div><div class="hide link depth-4"><a href="/api/providers/provider/#inspection-methods">Inspection Methods</a></div><div class="hide link depth-3"><a href="/api/providers/jsonrpc-provider/">JSON-RPC Provider</a></div><div class="hide link depth-4"><a href="/api/providers/jsonrpc-provider/#jsonrpcprovider">JsonRpcProvider</a></div><div class="hide link depth-4"><a href="/api/providers/jsonrpc-provider/#jsonrpcsigner">JsonRpcSigner</a></div><div class="hide link depth-4"><a href="/api/providers/jsonrpc-provider/#jsonrpcuncheckedsigner">JsonRpcUncheckedSigner</a></div><div class="hide link depth-3"><a href="/api/providers/api-providers/">API Providers</a></div><div class="hide link depth-4"><a href="/api/providers/api-providers/#etherscanprovider">EtherscanProvider</a></div><div class="hide link depth-4"><a href="/api/providers/api-providers/#infuraprovider">InfuraProvider</a></div><div class="hide link depth-4"><a href="/api/providers/api-providers/#nodesmithprovider">NodesmithProvider</a></div><div class="hide link depth-4"><a href="/api/providers/api-providers/#alchemyprovider">AlchemyProvider</a></div><div class="hide link depth-3"><a href="/api/providers/other/">Other Providers</a></div><div class="hide link depth-4"><a href="/api/providers/other/#fallbackprovider">FallbackProvider</a></div><div class="hide link depth-4"><a href="/api/providers/other/#ipcprovider">IpcProvider</a></div><div class="hide link depth-3"><a href="/api/providers/types/">Types</a></div><div class="hide link depth-4"><a href="/api/providers/types/#blocks">Blocks</a></div>
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<a name="strings"></a><h1>Strings</h1>
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<p>Tra la la</p>
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<a name="bytes32-string"></a><a name="bytes32string"></a><h2>Bytes32String</h2>
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<p>A string in Solidity is length prefixed with its 256-bit (32 byte) length, which means that even short strings require 2 words (64 bytes) of storage.</p><p>In many cases, we deal with short strings, so instead of prefixing the string with its length, we can null-terminate it and fit it in a single word (32 bytes). Since we need only a single byte for the null termination, we can store strings up to 31 bytes long in a word.</p>
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<div class="definition"><div class="term"><b>Note:</b></div><div class="body"><p>Strings that are 31 <u><i>bytes</i></u> long may contain fewer than 31 <u><i>characters</i></u>, since UTF-8 requires multiple bytes to encode international characters.</p></div></div>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="method">parseBytes32String</span> ( <span class="param">aBytesLike</span> ) <span class="arrow">⇒</span> <span class="returns">string</span></div><div class="body"><p>Returns the decoded string represented by the <code class="inline">Bytes32</code> encoded data.</p></div></div>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="method">formatBytes32String</span> ( <span class="param">text</span> ) <span class="arrow">⇒</span> <span class="returns">string</span></div><div class="body"><p>Returns a <code class="inline">bytes32</code> string representation of <i>text</i>. If the length of <i>text</i> exceeds 31 bytes, it will throw an error.</p></div></div>
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<a name="utf8-string"></a><a name="utf-8-strings"></a><h2>UTF-8 Strings</h2>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="method">toUtf8Bytes</span> ( <span class="param">text</span> [ , <span class="param">form</span> = <span class="default-value">c</span><span class="param">urrent</span> ] ) <span class="arrow">⇒</span> <span class="returns">Uint8Array</span></div><div class="body"><p>Returns the UTF-8 bytes of <i>text</i>, optionally normalizing it using the <a href="/api/utils/strings/#unicode-normalization-form">UnicodeNormalizationForm</a> <i>form</i>.</p></div></div>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="method">toUtf8CodePoints</span> ( <span class="param">aBytesLike</span> [ , <span class="param">form</span> = <span class="default-value">c</span><span class="param">urrent</span> ] ) <span class="arrow">⇒</span> <span class="returns">Array< number ></span></div><div class="body"><p>Returns the Array of codepoints of <i>aBytesLike</i>, optionally normalizing it using the <a href="/api/utils/strings/#unicode-normalization-form">UnicodeNormalizationForm</a> <i>form</i>.</p><p><b>Note:</b> This function correctly splits each user-perceived character into its codepoint, accounting for surrogate pairs. This should not be confused with <code class="inline">string.split("")</code>, which destroys surrogate pairs, spliting between each UTF-16 codeunit instead.</p></div></div>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="method">toUtf8String</span> ( <span class="param">aBytesLike</span> [ , <span class="param">ignoreErrors</span> = <span class="default-value">f</span><span class="param">alse</span> ] ) <span class="arrow">⇒</span> <span class="returns">string</span></div><div class="body"><p>Returns the string represented by the UTF-8 bytes of <i>aBytesLike</i>. This will throw an error for invalid surrogates, overlong sequences or other UTF-8 issues, unless <i>ignoreErrors</i> is specified.</p></div></div>
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<a name="unicode-normalization-form"></a><a name="unicodenormalizationform"></a><h3>UnicodeNormalizationForm</h3>
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<p>There are several <a href="https://en.wikipedia.org/wiki/Unicode_equivalence">commonly used forms</a> when normalizing UTF-8 data, which allow strings to be compared or hashed in a stable way.</p>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="path">UnicodeNormalizationForm</span> . <span class="method">current</span></div><div class="body"><p>Maintain the current normalization form.</p></div></div>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="path">UnicodeNormalizationForm</span> . <span class="method">NFC</span></div><div class="body"><p>The Composed Normalization Form. This form uses single codepoints which represent the fully composed character.</p><p>For example, the <b>é</b> is a single codepoint, <code class="inline">0x00e9</code>.</p></div></div>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="path">UnicodeNormalizationForm</span> . <span class="method">NFD</span></div><div class="body"><p>The Decomposed Normalization Form. This form uses multiple codepoints (when necessary) to compose a character.</p><p>For example, the <b>é</b> is made up of two codepoints, <code class="inline">"0x0065"</code> (which is the letter <code class="inline">"e"</code>) and <code class="inline">"0x0301"</code> which is a special diacritic UTF-8 codepoint which indicates the previous character should have an acute accent.</p></div></div>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="path">UnicodeNormalizationForm</span> . <span class="method">NFKC</span></div><div class="body"><p>The Composed Normalization Form with Canonical Equivalence. The Canonical representation folds characters which have the same syntactic representation but different semantic meaning.</p><p>For example, the Roman Numeral <b>I</b>, which has a UTF-8 codepoint <code class="inline">"0x2160"</code>, is folded into the capital letter I, <code class="inline">"0x0049"</code>.</p></div></div>
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<div class="property"><div class="signature"><span class="path">utils</span> . <span class="path">UnicodeNormalizationForm</span> . <span class="method">NFKD</span></div><div class="body"><p>The Decomposed Normalization Form with Canonical Equivalence. See NFKC for more an example.</p></div></div>
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<div class="definition"><div class="term"><b>Note:</b></div><div class="body"><p>Only certain specified characters are folded in Canonical Equivalence, and thus it should not be considered a method to acheive <i>any</i> level of security from <a href="https://en.wikipedia.org/wiki/IDN_homograph_attack">homoglyph attacks</a>.</p></div></div><div class="footer"><div class="nav previous"><a href="/api/utils/hashing/"><span class="arrow">←</span>Hashing Algorithms</a></div> <div class="nav next"><a href="/cookbook/">Cookbook<span class="arrow">→</span></a></div></div><div class="copyright">The content of this site is licensed under the <a href="https://choosealicense.com/licenses/cc-by-4.0/">Creative Commons Attribution 4.0 International License</a>.</div></div><script src="/script.js" type="text/javascript"></script></body></html><!-- ContentHash:4c4f20e2336d5d4be36da878d01d2b93dd03c3ca012af05ed95823b16897efec -->
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