92 lines
2.9 KiB
TypeScript
92 lines
2.9 KiB
TypeScript
/**
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* Most interactions with Ethereum requires integer values, which use
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* the smallest magnitude unit.
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*
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* For example, imagine dealing with dollars and cents. Since dollars
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* are divisible, non-integer values are possible, such as ``$10.77``.
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* By using the smallest indivisible unit (i.e. cents), the value can
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* be kept as the integer ``1077``.
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*
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* When receiving decimal input from the user (as a decimal string),
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* the value should be converted to an integer and when showing a user
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* a value, the integer value should be converted to a decimal string.
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*
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* This creates a clear distinction, between values to be used by code
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* (integers) and values used for display logic to users (decimals).
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*
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* The native unit in Ethereum, //ether// is divisible to 18 decimal places,
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* where each individual unit is called a //wei//.
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*
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* @_subsection api/utils:Unit Conversion [about-units]
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*/
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import { assertArgument } from "./errors.js";
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import { FixedNumber } from "./fixednumber.js";
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import { getNumber } from "./maths.js";
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import type { BigNumberish, Numeric } from "../utils/index.js";
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const names = [
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"wei",
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"kwei",
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"mwei",
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"gwei",
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"szabo",
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"finney",
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"ether",
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];
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/**
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* Converts %%value%% into a //decimal string//, assuming %%unit%% decimal
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* places. The %%unit%% may be the number of decimal places or the name of
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* a unit (e.g. ``"gwei"`` for 9 decimal places).
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*
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*/
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export function formatUnits(value: BigNumberish, unit?: string | Numeric): string {
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let decimals = 18;
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if (typeof(unit) === "string") {
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const index = names.indexOf(unit);
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assertArgument(index >= 0, "invalid unit", "unit", unit);
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decimals = 3 * index;
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} else if (unit != null) {
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decimals = getNumber(unit, "unit");
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}
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return FixedNumber.fromValue(value, decimals, { decimals, width: 512 }).toString();
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}
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/**
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* Converts the //decimal string// %%value%% to a BigInt, assuming
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* %%unit%% decimal places. The %%unit%% may the number of decimal places
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* or the name of a unit (e.g. ``"gwei"`` for 9 decimal places).
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*/
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export function parseUnits(value: string, unit?: string | Numeric): bigint {
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assertArgument(typeof(value) === "string", "value must be a string", "value", value);
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let decimals = 18;
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if (typeof(unit) === "string") {
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const index = names.indexOf(unit);
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assertArgument(index >= 0, "invalid unit", "unit", unit);
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decimals = 3 * index;
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} else if (unit != null) {
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decimals = getNumber(unit, "unit");
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}
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return FixedNumber.fromString(value, { decimals, width: 512 }).value;
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}
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/**
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* Converts %%value%% into a //decimal string// using 18 decimal places.
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*/
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export function formatEther(wei: BigNumberish): string {
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return formatUnits(wei, 18);
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}
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/**
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* Converts the //decimal string// %%ether%% to a BigInt, using 18
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* decimal places.
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*/
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export function parseEther(ether: string): bigint {
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return parseUnits(ether, 18);
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}
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