30秒学会 JavaScript 片段 – forOwnRight

Iterates over all own properties of an object in reverse, running a callback for each one.

Use Object.keys(obj) to get all the properties of the object, Array.prototype.reverse() to reverse their order and Array.prototype.forEach() to run the provided function for each key-value pair. The callback receives three arguments – the value, the key and the object.

代码片段

const forOwnRight = (obj, fn) =>
  Object.keys(obj)
    .reverse()
    .forEach(key => fn(obj[key], key, obj));

使用样例

forOwnRight({ foo: 'bar', a: 1 }, v => console.log(v)); // 1, 'bar'