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defaults.ts
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defaults.ts
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import eq from './eq.js';
/** Used for built-in method references. */
const objectProto = Object.prototype;
/** Used to check objects for own properties. */
const hasOwnProperty = objectProto.hasOwnProperty;
/**
* Assigns own and inherited enumerable string keyed properties of source
* objects to the destination object for all destination properties that
* resolve to `undefined`. Source objects are applied from left to right.
* Once a property is set, additional values of the same property are ignored.
*
* **Note:** This method mutates `object`.
*
* @since 0.1.0
* @category Object
* @param {Object} object The destination object.
* @param {...Object} [sources] The source objects.
* @returns {Object} Returns `object`.
* @see defaultsDeep
* @example
*
* defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 })
* // => { 'a': 1, 'b': 2 }
*/
function defaults(object, ...sources) {
object = Object(object);
sources.forEach((source) => {
if (source != null) {
source = Object(source);
for (const key in source) {
const value = object[key];
if (
value === undefined ||
(eq(value, objectProto[key]) && !hasOwnProperty.call(object, key))
) {
object[key] = source[key];
}
}
}
});
return object;
}
export default defaults;