如何动态合并两个 JavaScript 对象的属性?
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2023-09-11
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运行时需要能够合并两个(非常简单)JavaScript 对象。比如我想:+ q* G" D! ]) D/ f) `9 O
var obj1 = { food: 'pizza',car: 'ford' }var obj2 = { animal: 'dog' }obj1.merge(obj2);//obj1 now has three properties: food,car,and animal
- }, X; A! R" _3 p* ]4 g, ^ 有没有内置的方法可以做到这一点?我不需要递归或合并函数,只需要平面对象上的方法。; ?; b3 M$ L" Z; K% i
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解决方案: & B5 E# ~& E; p. }) o* C5 ~
ECMAScript 2018年 标准方法% C9 F+ X9 x' b4 H
用对象传播:
) v/ q5 H2 |- O. B) X. X" ^let merged = {...obj1,...obj2};
2 d% B. p4 T% ]# w$ b7 q. ^ merged现在是 和 obj1并集obj2。中的属性obj2将覆盖obj1.
! M( V S0 O! d/** There's no limit to the number of objects you can merge. * Later properties overwrite earlier properties with the same name. */const allRules = {...obj1,...obj2,...obj3};
( S6 J) C+ e# {1 _6 W6 i 这也是语法MDN如果使用 文档。babel,你需要babel-plugin-transform-object-rest-spread只有插件才能工作。
- z/ ]& N4 K+ }) J; Z7 l" {+ a7 eECMAScript 2015 (ES6) 标准方法; Y! \6 o4 ?. i- f3 V& y
/* For the case in question,you would do: */Object.assign(obj1,obj2);/** There's no limit to the number of objects you can merge. * All objects get merged into the first object. * Only the object in the first argument is mutated and returned. * Later properties overwrite earlier properties with the same name. */const allRules = Object.assign({},obj1,obj2,obj3,etc);
+ U/ d. q% s+ u& f) X6 _ (见MDN JavaScript 参考)2 T/ S$ P6 l; ?5 e4 H, D
ES5 及早版本的方法8 }, [% \! ^( Q6 m8 Q; m6 W6 a
for (var attrname in obj2) { obj1[attrname] = obj2[attrname]; }+ E3 ^* O7 i' @0 {: K( Y9 x
请注意,如果您仍然想使用未修改的产品obj2的.obj1``obj1* |/ l$ m+ f3 E3 A( c7 A$ j* h' \
如果你使用的框架在你的原型上是废话,你必须通过类似的检查获得更好的体验hasOwnProperty,但该代码将适用于 99% 。
) w4 [9 v$ c! d: c" r示例函数:0 u5 s2 C! c& R. R# ]" L
/** * Overwrites obj1's values with obj2's and adds obj2's if non existent in obj1 * @param obj1 * @param obj2 * @returns obj3 a new object based on obj1 and obj2 */function merge_options(obj1,obj二、{ var obj3 = {}; for (var attrname in obj1) { obj3[attrname] = obj1[attrname]; for (var attrname in obj2) { obj3[attrname] = obj2[attrname]; return obj3;}
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