Javascript对象原型箭头功能不起作用[重复]

Question

我认为这真的很简单，但由于某种原因它不起作用。我想做一个点函数来检查多个对象属性：

Object.prototype.hasOwnProperties = (properties) => { return properties.every(prop => this.hasOwnProperty(prop)) }

var test = {
    foo: 'bar',
    baz: 'boz'
}

result = test.hasOwnProperties(['foo', 'baz'])
console.log(result)

我希望它返回true，因为test 包含foo 和baz，但它返回false。为什么以及如何解决？

Answer 1

You must not use arrow functions (=>) when working with prototypes and referencing their instances (i.e. this) because arrow functions are lexically scoped

Object.prototype.hasOwnProperties = function(properties) { return properties.every(prop => this.hasOwnProperty(prop)) }

var test = {
    foo: 'bar',
    baz: 'boz'
}

result = test.hasOwnProperties(['foo', 'baz'])
console.log(result)