112 lines
3.5 KiB
TypeScript
112 lines
3.5 KiB
TypeScript
/**
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* @license
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* Copyright Google Inc. All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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const enum Char {
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OpenParen = 40,
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CloseParen = 41,
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Colon = 58,
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Semicolon = 59,
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BackSlash = 92,
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QuoteNone = 0, // indicating we are not inside a quote
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QuoteDouble = 34,
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QuoteSingle = 39,
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}
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/**
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* Parses string representation of a style and converts it into object literal.
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*
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* @param value string representation of style as used in the `style` attribute in HTML.
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* Example: `color: red; height: auto`.
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* @returns an object literal. `{ color: 'red', height: 'auto'}`.
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*/
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export function parseStyle(value: string): {[key: string]: any} {
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const styles: {[key: string]: any} = {};
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let i = 0;
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let parenDepth = 0;
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let quote: Char = Char.QuoteNone;
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let valueStart = 0;
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let propStart = 0;
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let currentProp: string|null = null;
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let valueHasQuotes = false;
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while (i < value.length) {
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const token = value.charCodeAt(i++) as Char;
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switch (token) {
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case Char.OpenParen:
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parenDepth++;
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break;
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case Char.CloseParen:
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parenDepth--;
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break;
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case Char.QuoteSingle:
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// valueStart needs to be there since prop values don't
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// have quotes in CSS
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valueHasQuotes = valueHasQuotes || valueStart > 0;
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if (quote === Char.QuoteNone) {
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quote = Char.QuoteSingle;
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} else if (quote === Char.QuoteSingle && value.charCodeAt(i - 1) !== Char.BackSlash) {
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quote = Char.QuoteNone;
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}
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break;
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case Char.QuoteDouble:
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// same logic as above
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valueHasQuotes = valueHasQuotes || valueStart > 0;
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if (quote === Char.QuoteNone) {
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quote = Char.QuoteDouble;
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} else if (quote === Char.QuoteDouble && value.charCodeAt(i - 1) !== Char.BackSlash) {
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quote = Char.QuoteNone;
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}
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break;
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case Char.Colon:
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if (!currentProp && parenDepth === 0 && quote === Char.QuoteNone) {
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currentProp = hyphenate(value.substring(propStart, i - 1).trim());
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valueStart = i;
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}
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break;
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case Char.Semicolon:
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if (currentProp && valueStart > 0 && parenDepth === 0 && quote === Char.QuoteNone) {
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const styleVal = value.substring(valueStart, i - 1).trim();
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styles[currentProp] = valueHasQuotes ? stripUnnecessaryQuotes(styleVal) : styleVal;
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propStart = i;
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valueStart = 0;
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currentProp = null;
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valueHasQuotes = false;
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}
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break;
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}
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}
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if (currentProp && valueStart) {
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const styleVal = value.substr(valueStart).trim();
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styles[currentProp] = valueHasQuotes ? stripUnnecessaryQuotes(styleVal) : styleVal;
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}
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return styles;
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}
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export function stripUnnecessaryQuotes(value: string): string {
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const qS = value.charCodeAt(0);
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const qE = value.charCodeAt(value.length - 1);
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if (qS == qE && (qS == Char.QuoteSingle || qS == Char.QuoteDouble)) {
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const tempValue = value.substring(1, value.length - 1);
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// special case to avoid using a multi-quoted string that was just chomped
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// (e.g. `font-family: "Verdana", "sans-serif"`)
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if (tempValue.indexOf('\'') == -1 && tempValue.indexOf('"') == -1) {
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value = tempValue;
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}
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}
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return value;
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}
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export function hyphenate(value: string): string {
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return value.replace(/[a-z][A-Z]/g, v => {
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return v.charAt(0) + '-' + v.charAt(1);
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}).toLowerCase();
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}
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