将Array＃reduce与帮助器对象一起使用可以对相似的对象进行分组。对于每个对象，检查合并的shape和是否color存在于帮助器中。如果不是，请使用Object＃assign添加到帮助器中以创建对象的副本，然后将其压入数组。如果是这样，请将其值添加到used和instances。
var arr = [{"shape":"square","color":"red","used":1,"instances":1},{"shape":"square","color":"red","used":2,"instances":1},{"shape":"circle","color":"blue","used":0,"instances":0},{"shape":"square","color":"blue","used":4,"instances":4},{"shape":"circle","color":"red","used":1,"instances":1},{"shape":"circle","color":"red","used":1,"instances":0},{"shape":"square","color":"blue","used":4,"instances":5},{"shape":"square","color":"red","used":2,"instances":1}];
var helper = {};
var result = arr.reduce(function(r, o) {
var key = o.shape + '-' + o.color;
if(!helper[key]) {
helper[key] = Object.assign({}, o); // create a copy of o
r.push(helper[key]);
} else {
helper[key].used += o.used;
helper[key].instances += o.instances;
}
return r;
}, []);
console.log(result);
如果你可以使用ES6，您可以使用地图收集的值，然后将其转换回一个数组蔓延的地图＃值：
const arr = [{"shape":"square","color":"red","used":1,"instances":1},{"shape":"square","color":"red","used":2,"instances":1},{"shape":"circle","color":"blue","used":0,"instances":0},{"shape":"square","color":"blue","used":4,"instances":4},{"shape":"circle","color":"red","used":1,"instances":1},{"shape":"circle","color":"red","used":1,"instances":0},{"shape":"square","color":"blue","used":4,"instances":5},{"shape":"square","color":"red","used":2,"instances":1}];
const result = [...arr.reduce((r, o) => {
const key = o.shape + '-' + o.color;
const item = r.get(key) || Object.assign({}, o, {
used: 0,
instances: 0
});
item.used += o.used;
item.instances += o.instances;
return r.set(key, item);
}, new Map).values()];
console.log(result);
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