不可变 JS 比较嵌套结构

2022-01-25 00:00:00 compare javascript immutable.js

我有 2 个嵌套结构 newState 和 newState1.

I have 2 nested structures newState and newState1.

但是当我比较它们时，equals() 或 Immutable.is() 返回 false.这些结构中的值相同.

But when I compare their, equals() or Immutable.is() returned false. The values in these structures identical.

如何正确比较newState和newState1?

var grid = {
    editable: false,
    widgets: [{
        name: 'Some widget',
        type: 'List',
        defaultDataSource: 'daily',
        dataSources: {}
    }, {
        name: 'Some widget1',
        type: 'List',
        defaultDataSource: 'daily',
        dataSources: {}
    }]
};

var state = Immutable.fromJS(grid);

var newState = state.updateIn(['widgets'], function (list) {
    return list.push(Immutable.Map({
        name: 'Some widget2',
        type: 'List',
        defaultDataSource: 'daily',
        dataSources: {}
    }));
});

var newState1 = state.updateIn(['widgets'], function (list) {
    return list.push(Immutable.Map({
        name: 'Some widget2',
        type: 'List',
        defaultDataSource: 'daily',
        dataSources: {}
    }));
});

console.log(state.toJS(), newState.toJS(), newState1.toJS());

console.log(newState.equals(newState1)); //false

JSFiddle 中的代码:https://jsfiddle.net/z3xuagwm/

Code in JSFiddle: https://jsfiddle.net/z3xuagwm/

推荐答案

好像immutablejs不做深度转换，所以如果你的value是object，就一直是object.

It seems that immutablejs don't do deep conversion, so if your value is object, it stays to be object.

由于您在每个更新步骤中创建不同的对象，并且当您相互比较时，这些对象将被视为不同，因此您还应该将其转换为 Immutable.Map 对象，以使比较为真.

As you're creating different object in each update step, and those objects will be treat different when you compare to each other, so you should also convert it to Immutable.Map object, to make the compare be true.

// Primitives.
var test1 = Immutable.Map({
    a: 'a', 
    b: 'b', 
    c: 'c'
});
var test2 = Immutable.Map({
    a: 'a',
    b: 'b',
    c: 'c'
});
console.log('Test primitive', test1.equals(test2)); // true

// Object
test1 = Immutable.Map({
    a: 'a',
    b: 'b',
    c: {}
});
test2 = Immutable.Map({
    a: 'a',
    b: 'b',
    c: {}
});
console.log('Test object', test1.equals(test2));  // false
// Its because
var a = {};
var b = {};
console.log('a === b?', a === b); // false

// Convert
test1 = Immutable.Map({
    a: 'a',
    b: 'b',
    c: Immutable.Map({})
});
test2 = Immutable.Map({
    a: 'a',
    b: 'b',
    c: Immutable.Map({})
});
console.log('Test converted', test1.equals(test2)); // true

<script src="https://cdnjs.cloudflare.com/ajax/libs/immutable/3.7.5/immutable.min.js"></script>

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