[JS] Object.assign 合併物件

Question

[JS] Object.assign 合併物件

CityRay opened this issue 8 years ago · comments

Object.assign 合併為一個新的物件，並建立新的 array

Method 1 (rest parameter)

    // ES6
    let state = {
        todos: [{
            id: 0,
            completed: false,
            text: 'Initial todo for demo purposes'
        }]
    }

    let newObj = Object.assign({}, state, {
        //建立一個新array，不會影響到原本的array
        todos: [{
            id: 1,
            text: "new text",
            completed: false
        }, ...state.todos]
    })

    console.log(newObj)
    console.log(state)

Method 2 (array concat)

    let newObj = Object.assign({}, state)

    //建立一個新array，不會影響到原本的array
    newObj.todos = state.todos.concat({
                    id: 1,
                    text: "new text",
                    completed: false
                })

    console.log(newObj)
    console.log(state)

Method 3 (array filter)

    let state = {
        todos: [{
            id: 0,
            completed: false,
            text: 'Initial todo for demo purposes'
        },
        {
            id: 1,
            completed: false,
            text: 'New Text2'
        }]
    }

    let newObj = Object.assign({}, state)

    //建立一個新array，不會影響到原本的array
    newObj.todos = state.todos.filter((val) => val.id >= 0)
    newObj.todos.push({id:3, text: 'new text3', completed: true})

    console.log(newObj)
    console.log(state)

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