47 lines
1.4 KiB
JavaScript
47 lines
1.4 KiB
JavaScript
'use strict';
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var numberIsNan = require('number-is-nan');
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module.exports = function (x) {
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if (numberIsNan(x)) {
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return false;
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}
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// https://github.com/nodejs/io.js/blob/cff7300a578be1b10001f2d967aaedc88aee6402/lib/readline.js#L1369
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// code points are derived from:
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// http://www.unix.org/Public/UNIDATA/EastAsianWidth.txt
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if (x >= 0x1100 && (
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x <= 0x115f || // Hangul Jamo
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0x2329 === x || // LEFT-POINTING ANGLE BRACKET
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0x232a === x || // RIGHT-POINTING ANGLE BRACKET
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// CJK Radicals Supplement .. Enclosed CJK Letters and Months
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(0x2e80 <= x && x <= 0x3247 && x !== 0x303f) ||
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// Enclosed CJK Letters and Months .. CJK Unified Ideographs Extension A
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0x3250 <= x && x <= 0x4dbf ||
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// CJK Unified Ideographs .. Yi Radicals
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0x4e00 <= x && x <= 0xa4c6 ||
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// Hangul Jamo Extended-A
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0xa960 <= x && x <= 0xa97c ||
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// Hangul Syllables
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0xac00 <= x && x <= 0xd7a3 ||
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// CJK Compatibility Ideographs
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0xf900 <= x && x <= 0xfaff ||
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// Vertical Forms
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0xfe10 <= x && x <= 0xfe19 ||
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// CJK Compatibility Forms .. Small Form Variants
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0xfe30 <= x && x <= 0xfe6b ||
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// Halfwidth and Fullwidth Forms
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0xff01 <= x && x <= 0xff60 ||
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0xffe0 <= x && x <= 0xffe6 ||
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// Kana Supplement
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0x1b000 <= x && x <= 0x1b001 ||
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// Enclosed Ideographic Supplement
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0x1f200 <= x && x <= 0x1f251 ||
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// CJK Unified Ideographs Extension B .. Tertiary Ideographic Plane
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0x20000 <= x && x <= 0x3fffd)) {
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return true;
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}
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return false;
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}
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