@wix/css-property-parser/dist/evaluators/number.js

A comprehensive TypeScript library for parsing and serializing CSS property values with full MDN specification compliance

// Number data type parser
// Handles parsing of CSS numeric values according to MDN specification
// https://developer.mozilla.org/en-US/docs/Web/CSS/number
// and reconstruction back to CSS string
import { parse as parseCSSVariable, toCSSValue as cssVariableToCSSValue } from './css-variable.js';
import { isCssVariable, isGlobalKeyword } from '../utils/shared-utils.js';
import { parseCalcFunction, cssFunctionToCSSValue } from '../utils/css-function-parser.js';
/**
 * Parses a CSS number value into structured components
 * Following MDN specification: https://developer.mozilla.org/en-US/docs/Web/CSS/number
 * @param value - The CSS number value string
 * @returns Parsed number object or null if invalid
 */
export function parse(value) {
    if (!value || typeof value !== 'string') {
        return null;
    }
    const trimmed = value.trim();
    if (trimmed === '')
        return null;
    // CSS variables - ALWAYS CHECK FIRST
    if (isCssVariable(trimmed)) {
        return parseCSSVariable(trimmed);
    }
    // Handle global keywords per MDN
    if (isGlobalKeyword(trimmed)) {
        return {
            type: 'keyword',
            keyword: trimmed.toLowerCase()
        };
    }
    // Handle calc() expressions
    const calcResult = parseCalcFunction(trimmed);
    if (calcResult) {
        return calcResult;
    }
    // MDN number pattern: integer or fractional, no unit
    // Supports scientific notation as per CSS spec
    const numberPattern = /^[+-]?(\d+\.?\d*|\.\d+)([eE][+-]?\d+)?$/;
    if (!numberPattern.test(trimmed)) {
        return null;
    }
    const numValue = parseFloat(trimmed);
    if (isNaN(numValue)) {
        return null;
    }
    // Normalize -0 to 0
    const normalizedValue = numValue === 0 ? 0 : numValue;
    return {
        type: 'number',
        value: normalizedValue
    };
}
/**
 * Converts a parsed number back to a CSS value string
 * @param parsed - The parsed number object
 * @returns CSS value string or null if invalid
 */
export function toCSSValue(parsed) {
    if (!parsed) {
        return null;
    }
    // Handle CSS variables
    if ('CSSvariable' in parsed) {
        return cssVariableToCSSValue(parsed);
    }
    // Handle keywords
    if ('keyword' in parsed) {
        return parsed.keyword;
    }
    // Handle calc expressions
    if ('expression' in parsed) {
        return cssFunctionToCSSValue(parsed);
    }
    // Handle regular number values (no unit per MDN)
    if ('value' in parsed) {
        return parsed.value.toString();
    }
    return null;
}