记一下Object.assign()用法
用于对象的合并,将源对象(source)的所有可枚举属性,复制到目标对象(target)。
const target = {a: 1};
const source1 = {b: 2};
const source2 = {c: 3};
Object.assign(target, source1, source2);
console.log(target)// {a:1, b:2, c:3}
const obj = {a: 1};
console.log(Object.is(Object.assign(obj), obj))//true
console.log(Object.assign(2))
console.log(typeof Object.assign(2))//object
console.log(Object.assign(undefined))//报错
console.log(Object.assign(null))//报错
let obj1 = {a: 1};
console.log(Object.is(Object.assign(obj1, undefined), obj1));
console.log(Object.assign(obj1, null) === obj1);
const v1 = 'abc';
const v2 = true;
const v3 = 10;
const v4 = {'Symbol':0};
const obj2 = Object.assign({}, v1, v2, v3,v4);
console.log(obj2);
Object.assign({b: 'c'},
Object.defineProperty({}, 'invisible', {
enumerable: false,
value: 'hello'
})
)
// { b: 'c' }
Object.assign({a: 'b'}, {[Symbol('c')]: 'd'})
console.log(Object.assign({a: 'b'}, {[Symbol('c')]: 'd'}))
const obj3 = {a: {b:1}};
const obj4 = Object.assign({}, obj3);
obj3.a.b = 2;
console.log(obj4.a.b)
const target1 = {a: 8};
const source3 = {a: 9};
console.log(Object.assign(target1, source3))
var obj5 = Object.assign([1, 2, 3], [4, 5]);
console.log(obj5);
const source4 = {
get foo() {return 1}
}
const target4 = {};
console.log(Object.assign(target4, source4));
class Point {
constructor (x, y) {
Object.assign(this, {x, y})
}
}
Object.assign(SomeClass.prototype, {
someMethod(arg1, arg2) {},
anotherMethod() {}
});
function clone(origin) {
return Object.assign({}, origin);
}
const merge = (target, ...sources) => Object.assign(target, ...sources);
const DEFAULTS = {
logLevel: 0,
outputFormat: 'html'
};
function processContent(options) {
options = Object.assign({}, DEFAULTS, options);
console.log(options);
}