microbundle/src/lib/option-normalization.js

/**
 * Convert booleans and int define= values to literals.
 * This is more intuitive than `microbundle --define A=1` producing A="1".
 */
export function toReplacementExpression(value, name) {
	// --define A="1",B='true' produces string:
	const matches = value.match(/^(['"])(.+)\1$/);
	if (matches) {
		return [JSON.stringify(matches[2]), name];
	}

	// --define @assign=Object.assign replaces expressions with expressions:
	if (name[0] === '@') {
		return [value, name.substring(1)];
	}

	// --define A=1,B=true produces int/boolean literal:
	if (/^(true|false|\d+)$/i.test(value)) {
		return [value, name];
	}

	// default: string literal
	return [JSON.stringify(value), name];
}

/**
 * Parses values of the form "$=jQuery,React=react" into key-value object pairs.
 */
export function parseMappingArgument(globalStrings, processValue) {
	const globals = {};
	globalStrings.split(',').forEach(globalString => {
		let [key, value] = globalString.split('=');
		if (processValue) {
			const r = processValue(value, key);
			if (r !== undefined) {
				if (Array.isArray(r)) {
					[value, key] = r;
				} else {
					value = r;
				}
			}
		}
		globals[key] = value;
	});
	return globals;
}

/**
 * Parses values of the form "$=jQuery,React=react" into key-value object pairs.
 */
export function parseAliasArgument(aliasStrings) {
	return aliasStrings.split(',').map(str => {
		let [key, value] = str.split('=');
		return { find: key, replacement: value };
	});
}