59 lines
1.6 KiB
JavaScript
59 lines
1.6 KiB
JavaScript
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/**
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* @fileoverview Utilities to operate on strings.
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* @author Stephen Wade
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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// eslint-disable-next-line no-control-regex -- intentionally including control characters
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const ASCII_REGEX = /^[\u0000-\u007f]*$/u;
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/** @type {Intl.Segmenter | undefined} */
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let segmenter;
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//------------------------------------------------------------------------------
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// Public Interface
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//------------------------------------------------------------------------------
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/**
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* Converts the first letter of a string to uppercase.
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* @param {string} string The string to operate on
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* @returns {string} The converted string
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*/
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function upperCaseFirst(string) {
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if (string.length <= 1) {
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return string.toUpperCase();
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}
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return string[0].toUpperCase() + string.slice(1);
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}
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/**
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* Counts graphemes in a given string.
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* @param {string} value A string to count graphemes.
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* @returns {number} The number of graphemes in `value`.
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*/
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function getGraphemeCount(value) {
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if (ASCII_REGEX.test(value)) {
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return value.length;
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}
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segmenter ??= new Intl.Segmenter("en-US"); // en-US locale should be supported everywhere
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let graphemeCount = 0;
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// eslint-disable-next-line no-unused-vars -- for-of needs a variable
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for (const unused of segmenter.segment(value)) {
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graphemeCount++;
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}
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return graphemeCount;
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}
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module.exports = {
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upperCaseFirst,
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getGraphemeCount
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};
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