Assign default values for object properties
Assigns default values for all properties in an object that are undefined.
- Use
Object.assign()to create a new empty object and copy the original one to maintain key order. - Use
Array.prototype.reverse()and the spread operator (...) to combine the default values from left to right. - Finally, use
objagain to overwrite properties that originally had a value.
const defaults = (obj, ...defs) => Object.assign({}, obj, ...defs.reverse(), obj); defaults({ a: 1 }, { b: 2 }, { b: 6 }, { a: 3 }); // { a: 1, b: 2 }
