38 lines
741 B
JavaScript
38 lines
741 B
JavaScript
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'use strict';
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var stripAnsi = require('strip-ansi');
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var codePointAt = require('code-point-at');
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var isFullwidthCodePoint = require('is-fullwidth-code-point');
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// https://github.com/nodejs/io.js/blob/cff7300a578be1b10001f2d967aaedc88aee6402/lib/readline.js#L1345
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module.exports = function (str) {
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if (typeof str !== 'string' || str.length === 0) {
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return 0;
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}
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var width = 0;
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str = stripAnsi(str);
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for (var i = 0; i < str.length; i++) {
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var code = codePointAt(str, i);
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// ignore control characters
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if (code <= 0x1f || (code >= 0x7f && code <= 0x9f)) {
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continue;
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}
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// surrogates
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if (code >= 0x10000) {
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i++;
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}
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if (isFullwidthCodePoint(code)) {
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width += 2;
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} else {
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width++;
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}
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}
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return width;
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};
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