Function optionsFromArguments

Tone/core/util/Defaults.ts:56–87

(
	defaults: T,
	argsArray: IArguments,
	keys: Array<keyof T> = [],
	objKey?: keyof T,
)

 * Convert an args array into an object.
 */
export function optionsFromArguments<T extends object>(
	defaults: T,
	argsArray: IArguments,
	keys: Array<keyof T> = [],
	objKey?: keyof T,
): T {
	const opts: Partial<T> = {};
	const args = Array.from(argsArray);
	// if the first argument is an object and has an object key
	if (isObject(args[0]) && objKey && !Reflect.has(args[0], objKey)) {
		// if it's not part of the defaults
		const partOfDefaults = Object.keys(args[0]).some(key => Reflect.has(defaults, key));
		if (!partOfDefaults) {
			// merge that key
			deepMerge(opts, { [objKey]: args[0] });
			// remove the obj key from the keys
			keys.splice(keys.indexOf(objKey), 1);
			// shift the first argument off
			args.shift();
		}
	}
	if (args.length === 1 && isObject(args[0])) {
		deepMerge(opts, args[0]);
	} else {
		for (let i = 0; i < keys.length; i++) {
			if (isDefined(args[i])) {
				opts[keys[i]] = args[i];
			}
		}
	}
	return deepMerge(defaults, opts);
}

/**
 * Return this instances default values by calling Constructor.getDefaults()