Ratio.js•1.69 kB
import { isDigit, Delim, Number as NumberToken } from '../../tokenizer/index.js';
const SOLIDUS = 0x002F; // U+002F SOLIDUS (/)
const FULLSTOP = 0x002E; // U+002E FULL STOP (.)
// Terms of <ratio> should be a positive numbers (not zero or negative)
// (see https://drafts.csswg.org/mediaqueries-3/#values)
// However, -o-min-device-pixel-ratio takes fractional values as a ratio's term
// and this is using by various sites. Therefore we relax checking on parse
// to test a term is unsigned number without an exponent part.
// Additional checking may be applied on lexer validation.
function consumeNumber() {
this.skipSC();
const value = this.consume(NumberToken);
for (let i = 0; i < value.length; i++) {
const code = value.charCodeAt(i);
if (!isDigit(code) && code !== FULLSTOP) {
this.error('Unsigned number is expected', this.tokenStart - value.length + i);
}
}
if (Number(value) === 0) {
this.error('Zero number is not allowed', this.tokenStart - value.length);
}
return value;
}
export const name = 'Ratio';
export const structure = {
left: String,
right: String
};
// <positive-integer> S* '/' S* <positive-integer>
export function parse() {
const start = this.tokenStart;
const left = consumeNumber.call(this);
let right;
this.skipSC();
this.eatDelim(SOLIDUS);
right = consumeNumber.call(this);
return {
type: 'Ratio',
loc: this.getLocation(start, this.tokenStart),
left,
right
};
}
export function generate(node) {
this.token(NumberToken, node.left);
this.token(Delim, '/');
this.token(NumberToken, node.right);
}