javascript - reactjs 中的 this.state.todolist.push() 返回一个数字？

Question

当我在reactjs中使用this.state.todolist.push()时，它返回一个数字？但是用 concat 替换 push 会返回正确的值。

var ToDosBox = React.createClass({
    getInitialState:function(){
        return {
            taskList:[]
        }
    },
    addCallback:function(e,value){
        var tasks = this.state.taskList.push({taskName:value,author:'test',time:'10:15'});
        //console.log(tasks);
        this.setState({taskList:tasks});
    },
    render:function(){
        return (
            <div className="todos-box">
                <InputBox ref="inputBox" callback={this.addCallback} />
                <h3>Todo List</h3>
                <ToDosList items={this.state.taskList} />
            </div>
            )
    }
})

Answer 1

是因为.push

returns the new length property of the object upon which the method was called.

你不需要变量tasks，你可以传递给setState方法this.state.taskList，像这样

addCallback: function (e, value) {
    this.state.taskList.push({
        taskName: value, author: 'test', time: '10:15'
    });

    this.setState({taskList: this.state.taskList});
}

Example