120 lines
2.2 KiB
JavaScript
120 lines
2.2 KiB
JavaScript
var minus = "-".charCodeAt(0);
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var plus = "+".charCodeAt(0);
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var dot = ".".charCodeAt(0);
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var exp = "e".charCodeAt(0);
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var EXP = "E".charCodeAt(0);
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// Check if three code points would start a number
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// https://www.w3.org/TR/css-syntax-3/#starts-with-a-number
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function likeNumber(value) {
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var code = value.charCodeAt(0);
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var nextCode;
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if (code === plus || code === minus) {
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nextCode = value.charCodeAt(1);
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if (nextCode >= 48 && nextCode <= 57) {
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return true;
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}
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var nextNextCode = value.charCodeAt(2);
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if (nextCode === dot && nextNextCode >= 48 && nextNextCode <= 57) {
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return true;
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}
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return false;
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}
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if (code === dot) {
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nextCode = value.charCodeAt(1);
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if (nextCode >= 48 && nextCode <= 57) {
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return true;
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}
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return false;
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}
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if (code >= 48 && code <= 57) {
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return true;
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}
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return false;
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}
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// Consume a number
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// https://www.w3.org/TR/css-syntax-3/#consume-number
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module.exports = function(value) {
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var pos = 0;
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var length = value.length;
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var code;
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var nextCode;
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var nextNextCode;
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if (length === 0 || !likeNumber(value)) {
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return false;
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}
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code = value.charCodeAt(pos);
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if (code === plus || code === minus) {
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pos++;
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}
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while (pos < length) {
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code = value.charCodeAt(pos);
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if (code < 48 || code > 57) {
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break;
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}
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pos += 1;
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}
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code = value.charCodeAt(pos);
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nextCode = value.charCodeAt(pos + 1);
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if (code === dot && nextCode >= 48 && nextCode <= 57) {
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pos += 2;
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while (pos < length) {
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code = value.charCodeAt(pos);
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if (code < 48 || code > 57) {
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break;
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}
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pos += 1;
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}
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}
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code = value.charCodeAt(pos);
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nextCode = value.charCodeAt(pos + 1);
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nextNextCode = value.charCodeAt(pos + 2);
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if (
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(code === exp || code === EXP) &&
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((nextCode >= 48 && nextCode <= 57) ||
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((nextCode === plus || nextCode === minus) &&
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nextNextCode >= 48 &&
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nextNextCode <= 57))
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) {
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pos += nextCode === plus || nextCode === minus ? 3 : 2;
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while (pos < length) {
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code = value.charCodeAt(pos);
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if (code < 48 || code > 57) {
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break;
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}
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pos += 1;
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}
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}
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return {
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number: value.slice(0, pos),
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unit: value.slice(pos)
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};
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};
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