未处理的拒绝（TypeError）：散布不可迭代实例的无效尝试

Question

I get the error from the code:

 state: { route: 'signin', isSignedIn: false, news: {}, weather: {}, sports: [], clothes: {}, selectedTeam: "", user: { id: '', name: '', email: '', profimg: '', images: [], tasks: [] } } newTask = task => { const { user, tasks } = this.state; this.setState({ user: { ...user, tasks: [ ...tasks, task ] } }) } 

I provided the state structure, and the function. What is the problem? What the error means as non-iterable?

Answer 1

The array tasks is inside of object user .

You can execute a destructure statement as follow:

const { user, tasks = [user] } = this.state

 let state = { route: 'signin', isSignedIn: false, news: {}, weather: {}, sports: [], clothes: {}, selectedTeam: "", user: { id: '', name: '', email: '', profimg: '', images: [], tasks: ['EleFromStack'] } }; let newTask = task => { const { user, tasks = [user] } = state; console.log(JSON.stringify({ user: { ...user, tasks: [ ...tasks, task ] } }, null, 2)) }; newTask('SOQuestion') 

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