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

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

// Angle data type parser
// Handles parsing of CSS angle values according to MDN specification
// https://developer.mozilla.org/en-US/docs/Web/CSS/angle
import { parse as parseNumber } from './number.js';
import { parse as parseCSSVariable, toCSSValue as cssVariableToCSSValue } from './css-variable.js';
import { isCssVariable } from '../utils/shared-utils.js';
import { parseCalcFunction, cssFunctionToCSSValue } from '../utils/css-function-parser.js';
// Common angle unit patterns
const ANGLE_UNIT_REGEX = /^(-?(?:\d+\.?\d*|\.\d+)(?:[eE][+-]?\d+)?)(deg|grad|rad|turn)$/i;
/**
 * Parses a CSS angle value into structured components
 * @param value - The CSS angle value string
 * @returns Parsed angle object or null if invalid
 */
export function parse(value) {
    if (!value || typeof value !== 'string') {
        return null;
    }
    const trimmed = value.trim();
    if (trimmed === '')
        return null;
    // CSS variables - ALWAYS CHECK FIRST
    if (isCssVariable(trimmed)) {
        return parseCSSVariable(trimmed);
    }
    // Handle calc() expressions
    const calcResult = parseCalcFunction(trimmed);
    if (calcResult) {
        return calcResult;
    }
    // Handle zero (can be unitless)
    if (trimmed === '0') {
        return {
            type: 'angle',
            value: 0,
            unit: 'deg'
        };
    }
    // Match angle with unit
    const match = trimmed.match(ANGLE_UNIT_REGEX);
    if (!match) {
        return null;
    }
    const [, valueStr, unitStr] = match;
    const numberValue = parseNumber(valueStr);
    if (!numberValue || !('value' in numberValue)) {
        return null;
    }
    const unit = unitStr.toLowerCase();
    return {
        type: 'angle',
        value: numberValue.value,
        unit
    };
}
/**
 * Converts a parsed angle back to a CSS value string
 * @param parsed - The parsed angle object
 * @returns CSS value string or null if invalid
 */
export function toCSSValue(parsed) {
    if (!parsed) {
        return null;
    }
    // Handle CSS variables
    if ('CSSvariable' in parsed) {
        return cssVariableToCSSValue(parsed);
    }
    // Handle calc expressions
    if ('expression' in parsed) {
        return cssFunctionToCSSValue(parsed);
    }
    // Handle regular angle values
    if ('value' in parsed && 'unit' in parsed) {
        // Special case: zero can be unitless
        if (parsed.value === 0) {
            return '0';
        }
        return `${parsed.value}${parsed.unit}`;
    }
    return null;
}