过滤器无法使用匿名功能

Question

I'm trying to learn react so I know this isn't the best way to make a copy but why doesn't the following work:

var allItems = this.state.items;
allItems =allItems.filter(function(e){return e;});

I keep getting filter is not a function

Answer 1

Since this.state.items is an Object, not an Array, you will need to loop over the keys like so:

var filteredArray = [];
Object.keys(allItems).forEach(function(key) {
    // do something with each item
    console.log(key + ': ' + allItems[key]);
    // like add it to a filtered array, conditionally if you want to:
    filteredArray.push(allItems[key]);
});