[英]Dynamically set property of nested object
我有一个 object，它可以是任意数量的级别，并且可以具有任何现有属性。 例如：
var obj = {
db: {
mongodb: {
host: 'localhost'
}
}
};
对此，我想设置（或覆盖）如下属性：
set('db.mongodb.user', 'root');
// or:
set('foo.bar', 'baz');
属性字符串可以有任何深度，值可以是任何类型/事物。
如果属性键已经存在，则不需要合并对象和 arrays 作为值。
上一个示例将生成以下 object：
var obj = {
db: {
mongodb: {
host: 'localhost',
user: 'root'
}
},
foo: {
bar: baz
}
};
我怎样才能实现这样的function？
此函数使用您指定的参数，应添加/更新obj容器中的数据。 请注意，您需要跟踪obj模式中的哪些元素是容器，哪些是值（字符串、整数等），否则您将开始抛出异常。
obj = {}; // global object
function set(path, value) {
var schema = obj; // a moving reference to internal objects within obj
var pList = path.split('.');
var len = pList.length;
for(var i = 0; i < len-1; i++) {
var elem = pList[i];
if( !schema[elem] ) schema[elem] = {}
schema = schema[elem];
}
schema[pList[len-1]] = value;
}
set('mongo.db.user', 'root');
Lodash 有一个_.set()方法。
_.set(obj, 'db.mongodb.user', 'root');
_.set(obj, 'foo.bar', 'baz');
有点晚了，但这是一个非图书馆的，更简单的答案：
/**
* Dynamically sets a deeply nested value in an object.
* Optionally "bores" a path to it if its undefined.
* @function
* @param {!object} obj - The object which contains the value you want to change/set.
* @param {!array} path - The array representation of path to the value you want to change/set.
* @param {!mixed} value - The value you want to set it to.
* @param {boolean} setrecursively - If true, will set value of non-existing path as well.
*/
function setDeep(obj, path, value, setrecursively = false) {
path.reduce((a, b, level) => {
if (setrecursively && typeof a[b] === "undefined" && level !== path.length){
a[b] = {};
return a[b];
}
if (level === path.length){
a[b] = value;
return value;
}
return a[b];
}, obj);
}
我制作的这个功能可以完全满足您的需求，而且还可以做得更多。
假设我们要更改深度嵌套在此对象中的目标值：
let myObj = {
level1: {
level2: {
target: 1
}
}
}
所以我们会像这样调用我们的函数：
setDeep(myObj, ["level1", "level2", "target1"], 3);
将导致：
myObj = { level1: { level2: { target: 3 } } }
如果对象不存在，将 set recursively 标志设置为 true 将设置对象。
setDeep(myObj, ["new", "path", "target"], 3, true);
将导致：
obj = myObj = {
new: {
path: {
target: 3
}
},
level1: {
level2: {
target: 3
}
}
}
我只是用ES6+递归写了一个小函数来达到目的。
updateObjProp = (obj, value, propPath) => {
const [head, ...rest] = propPath.split('.');
!rest.length
? obj[head] = value
: this.updateObjProp(obj[head], value, rest.join('.'));
}
const user = {profile: {name: 'foo'}};
updateObjProp(user, 'fooChanged', 'profile.name');
我在反应更新状态时经常使用它，它对我来说效果很好。
我们可以使用递归函数：
/**
* Sets a value of nested key string descriptor inside a Object.
* It changes the passed object.
* Ex:
* let obj = {a: {b:{c:'initial'}}}
* setNestedKey(obj, ['a', 'b', 'c'], 'changed-value')
* assert(obj === {a: {b:{c:'changed-value'}}})
*
* @param {[Object]} obj Object to set the nested key
* @param {[Array]} path An array to describe the path(Ex: ['a', 'b', 'c'])
* @param {[Object]} value Any value
*/
export const setNestedKey = (obj, path, value) => {
if (path.length === 1) {
obj[path] = value
return
}
return setNestedKey(obj[path[0]], path.slice(1), value)
}
更简单！
受到@bpmason1 回答的启发：
function leaf(obj, path, value) {
const pList = path.split('.');
const key = pList.pop();
const pointer = pList.reduce((accumulator, currentValue) => {
if (accumulator[currentValue] === undefined) accumulator[currentValue] = {};
return accumulator[currentValue];
}, obj);
pointer[key] = value;
return obj;
}
例子：
const obj = {
boats: {
m1: 'lady blue'
}
};
leaf(obj, 'boats.m1', 'lady blue II');
leaf(obj, 'boats.m2', 'lady bird');
console.log(obj); // { boats: { m1: 'lady blue II', m2: 'lady bird' } }
Lodash 有一个叫做update的方法，它完全符合你的需要。
此方法接收以下参数：
在您的示例中，它看起来像这样：
_.update(obj, 'db.mongodb.user', function(originalValue) {
return 'root'
})
ES6 也有一个非常酷的方法来使用Computed Property Name和Rest Parameter来做到这一点。
const obj = {
levelOne: {
levelTwo: {
levelThree: "Set this one!"
}
}
}
const updatedObj = {
...obj,
levelOne: {
...obj.levelOne,
levelTwo: {
...obj.levelOne.levelTwo,
levelThree: "I am now updated!"
}
}
}
如果levelThree是一个动态属性即设置任何的财产levelTwo ，您可以使用[propertyName]: "I am now updated!" 其中propertyName包含levelTwo中的属性名称。
我想出了我自己的解决方案，使用纯 es6 和不会改变原始对象的递归。
const setNestedProp = (obj = {}, [first, ...rest] , value) => ({ ...obj, [first]: rest.length ? setNestedProp(obj[first], rest, value) : value }); const result = setNestedProp({}, ["first", "second", "a"], "foo"); const result2 = setNestedProp(result, ["first", "second", "b"], "bar"); console.log(result); console.log(result2);
我创建了用于根据正确答案按字符串设置和获取 obj 值的 要点。 您可以下载它或将其用作 npm/yarn 包。
// yarn add gist:5ceba1081bbf0162b98860b34a511a92
// npm install gist:5ceba1081bbf0162b98860b34a511a92
export const DeepObject = {
set: setDeep,
get: getDeep
};
// https://stackoverflow.com/a/6491621
function getDeep(obj: Object, path: string) {
path = path.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
path = path.replace(/^\./, ''); // strip a leading dot
const a = path.split('.');
for (let i = 0, l = a.length; i < l; ++i) {
const n = a[i];
if (n in obj) {
obj = obj[n];
} else {
return;
}
}
return obj;
}
// https://stackoverflow.com/a/18937118
function setDeep(obj: Object, path: string, value: any) {
let schema = obj; // a moving reference to internal objects within obj
const pList = path.split('.');
const len = pList.length;
for (let i = 0; i < len - 1; i++) {
const elem = pList[i];
if (!schema[elem]) {
schema[elem] = {};
}
schema = schema[elem];
}
schema[pList[len - 1]] = value;
}
// Usage
// import {DeepObject} from 'somePath'
//
// const obj = {
// a: 4,
// b: {
// c: {
// d: 2
// }
// }
// };
//
// DeepObject.set(obj, 'b.c.d', 10); // sets obj.b.c.d to 10
// console.log(DeepObject.get(obj, 'b.c.d')); // returns 10
我需要实现同样的事情，但是在 Node.js 中......所以，我发现了这个不错的模块： https : //www.npmjs.com/package/nested-property
例子：
var mod = require("nested-property");
var obj = {
a: {
b: {
c: {
d: 5
}
}
}
};
console.log(mod.get(obj, "a.b.c.d"));
mod.set(obj, "a.b.c.d", 6);
console.log(mod.get(obj, "a.b.c.d"));
扩展@bpmason1提供的公认答案，以支持字符串路径中的数组，例如字符串路径可以是'db.mongodb.users[0].name'和'db.mongodb.users[1].name' 。
它将设置属性值，如果不存在，将被创建。
var obj = {}; function set(path, value) { var schema = obj; var keysList = path.split('.'); var len = keysList.length; for (var i = 0; i < len - 1; i++) { var key = keysList[i]; // checking if key represents an array element eg users[0] if (key.includes('[')) { //getting propertyName 'users' form key 'users[0]' var propertyName = key.substr(0, key.length - key.substr(key.indexOf("["), key.length - key.indexOf("[")).length); if (!schema[propertyName]) { schema[propertyName] = []; } // schema['users'][getting index 0 from 'users[0]'] if (!schema[propertyName][parseInt(key.substr(key.indexOf("[") + 1, key.indexOf("]") - key.indexOf("[") - 1))]) { // if it doesn't exist create and initialise it schema = schema[propertyName][parseInt(key.substr(key.indexOf("[") + 1, key.indexOf("]") - key.indexOf("[") - 1))] = {}; } else { schema = schema[propertyName][parseInt(key.substr(key.indexOf("[") + 1, key.indexOf("]") - key.indexOf("[") - 1))]; } continue; } if (!schema[key]) { schema[key] = {}; } schema = schema[key]; } //loop ends // if last key is array element if (keysList[len - 1].includes('[')) { //getting propertyName 'users' form key 'users[0]' var propertyName = keysList[len - 1].substr(0, keysList[len - 1].length - keysList[len - 1].substr(keysList[len - 1].indexOf("["), keysList[len - 1].length - keysList[len - 1].indexOf("[")).length); if (!schema[propertyName]) { schema[propertyName] = []; } // schema[users][0] = value; schema[propertyName][parseInt(keysList[len - 1].substr(keysList[len - 1].indexOf("[") + 1, keysList[len - 1].indexOf("]") - keysList[len - 1].indexOf("[") - 1))] = value; } else { schema[keysList[len - 1]] = value; } } // will create if not exist set("mongo.db.users[0].name.firstname", "hii0"); set("mongo.db.users[1].name.firstname", "hii1"); set("mongo.db.users[2].name", { "firstname": "hii2" }); set("mongo.db.other", "xx"); console.log(obj); // will set if exist set("mongo.db.other", "yy"); console.log(obj);
如果您只需要更改更深层次的嵌套对象，那么另一种方法可能是引用该对象。 由于 JS 对象是由它们的引用处理的，因此您可以创建对具有字符串键访问权限的对象的引用。
例子：
// The object we want to modify:
var obj = {
db: {
mongodb: {
host: 'localhost',
user: 'root'
}
},
foo: {
bar: baz
}
};
var key1 = 'mongodb';
var key2 = 'host';
var myRef = obj.db[key1]; //this creates a reference to obj.db['mongodb']
myRef[key2] = 'my new string';
// The object now looks like:
var obj = {
db: {
mongodb: {
host: 'my new string',
user: 'root'
}
},
foo: {
bar: baz
}
};
另一种方法是使用递归来挖掘对象：
(function(root){
function NestedSetterAndGetter(){
function setValueByArray(obj, parts, value){
if(!parts){
throw 'No parts array passed in';
}
if(parts.length === 0){
throw 'parts should never have a length of 0';
}
if(parts.length === 1){
obj[parts[0]] = value;
} else {
var next = parts.shift();
if(!obj[next]){
obj[next] = {};
}
setValueByArray(obj[next], parts, value);
}
}
function getValueByArray(obj, parts, value){
if(!parts) {
return null;
}
if(parts.length === 1){
return obj[parts[0]];
} else {
var next = parts.shift();
if(!obj[next]){
return null;
}
return getValueByArray(obj[next], parts, value);
}
}
this.set = function(obj, path, value) {
setValueByArray(obj, path.split('.'), value);
};
this.get = function(obj, path){
return getValueByArray(obj, path.split('.'));
};
}
root.NestedSetterAndGetter = NestedSetterAndGetter;
})(this);
var setter = new this.NestedSetterAndGetter();
var o = {};
setter.set(o, 'a.b.c', 'apple');
console.log(o); //=> { a: { b: { c: 'apple'}}}
var z = { a: { b: { c: { d: 'test' } } } };
setter.set(z, 'a.b.c', {dd: 'zzz'});
console.log(JSON.stringify(z)); //=> {"a":{"b":{"c":{"dd":"zzz"}}}}
console.log(JSON.stringify(setter.get(z, 'a.b.c'))); //=> {"dd":"zzz"}
console.log(JSON.stringify(setter.get(z, 'a.b'))); //=> {"c":{"dd":"zzz"}}
迟到了 - 这是一个普通的 js 函数，它接受一个路径作为参数并返回修改后的对象/json
let orig_json = { string: "Hi", number: 0, boolean: false, object: { subString: "Hello", subNumber: 1, subBoolean: true, subObject: { subSubString: "Hello World" }, subArray: ["-1", "-2", "-3"] }, array: ["1", "2", "3"] } function changeValue(obj_path, value, json) { let keys = obj_path.split(".") let obj = { ...json }, tmpobj = {}, prevobj = {} for (let x = keys.length - 1; x >= 0; x--) { if (x == 0) { obj[keys[0]] = tmpobj } else { let toeval = 'json.' + keys.slice(0, x).join('.'); prevobj = { ...tmpobj } tmpobj = eval(toeval); if (x == keys.length - 1) tmpobj[keys[x]] = value else { tmpobj[keys[x]] = prevobj } } } return obj } let newjson = changeValue("object.subObject.subSubString", "Goodbye world", orig_json); console.log(newjson)
添加或覆盖属性的另一种解决方案：
function propertySetter(property, value) { const sampleObject = { string: "Hi", number: 0, boolean: false, object: { subString: "Hello", subNumber: 1, subBoolean: true, subObject: { subSubString: "Hello World", }, subArray: ["-1", "-2", "-3"], }, array: ["1", "2", "3"], }; const keys = property.split("."); const propertyName = keys.pop(); let propertyParent = sampleObject; while (keys.length > 0) { const key = keys.shift(); if (!(key in propertyParent)) { propertyParent[key] = {}; } propertyParent = propertyParent[key]; } propertyParent[propertyName] = value; return sampleObject; } console.log(propertySetter("object.subObject.anotherSubString", "Hello you")); console.log(propertySetter("object.subObject.subSubString", "Hello Earth")); console.log(propertySetter("object.subObject.nextSubString.subSubSubString", "Helloooo"));
如果你想要一个需要先前属性存在的函数，那么你可以使用这样的东西，它还会返回一个标志，说明它是否设法找到并设置了嵌套属性。
function set(obj, path, value) {
var parts = (path || '').split('.');
// using 'every' so we can return a flag stating whether we managed to set the value.
return parts.every((p, i) => {
if (!obj) return false; // cancel early as we havent found a nested prop.
if (i === parts.length - 1){ // we're at the final part of the path.
obj[parts[i]] = value;
}else{
obj = obj[parts[i]]; // overwrite the functions reference of the object with the nested one.
}
return true;
});
}
受 ClojureScript 的assoc-in ( https://github.com/clojure/clojurescript/blob/master/src/main/cljs/cljs/core.cljs#L5280 ) 启发，使用递归：
/**
* Associate value (v) in object/array (m) at key/index (k).
* If m is falsy, use new object.
* Returns the updated object/array.
*/
function assoc(m, k, v) {
m = (m || {});
m[k] = v;
return m;
}
/**
* Associate value (v) in nested object/array (m) using sequence of keys (ks)
* to identify the path to the nested key/index.
* If one of the values in the nested object/array doesn't exist, it adds
* a new object.
*/
function assoc_in(m={}, [k, ...ks], v) {
return ks.length ? assoc(m, k, assoc_in(m[k], ks, v)) : assoc(m, k, v);
}
/**
* Associate value (v) in nested object/array (m) using key string notation (s)
* (e.g. "k1.k2").
*/
function set(m, s, v) {
ks = s.split(".");
return assoc_in(m, ks, v);
}
笔记：
通过提供的实现，
assoc_in({"a": 1}, ["a", "b"], 2)
返回
{"a": 1}
在这种情况下，我希望它抛出错误。 如果需要，您可以在assoc添加检查以验证m是对象还是数组，否则抛出错误。
我试着简而言之写了这个set 方法，它可能对某人有帮助！
function set(obj, key, value) { let keys = key.split('.'); if(keys.length<2){ obj[key] = value; return obj; } let lastKey = keys.pop(); let fun = `obj.${keys.join('.')} = {${lastKey}: '${value}'};`; return new Function(fun)(); } var obj = { "hello": { "world": "test" } }; set(obj, "hello.world", 'test updated'); console.log(obj); set(obj, "hello.world.again", 'hello again'); console.log(obj); set(obj, "hello.world.again.onece_again", 'hello once again'); console.log(obj);
const set = (o, path, value) => {
const props = path.split('.');
const prop = props.shift()
if (props.length === 0) {
o[prop] = value
} else {
o[prop] = o[prop] ?? {}
set(o[prop], props.join('.'), value)
}
}
受 ImmutableJS setIn 方法的启发，该方法永远不会改变原始方法。 这适用于混合数组和对象嵌套值。
function setIn(obj = {}, [prop, ...rest], value) {
const newObj = Array.isArray(obj) ? [...obj] : {...obj};
newObj[prop] = rest.length ? setIn(obj[prop], rest, value) : value;
return newObj;
}
var obj = {
a: {
b: {
c: [
{d: 5}
]
}
}
};
const newObj = setIn(obj, ["a", "b", "c", 0, "x"], "new");
//obj === {a: {b: {c: [{d: 5}]}}}
//newObj === {a: {b: {c: [{d: 5, x: "new"}]}}}
如果您想深入更新或插入对象，请尝试以下操作：-
let init = {
abc: {
c: {1: 2, 3: 5, 0: {l: 3}},
d: 100
}
}
Object.prototype.deepUpdate = function(update){
let key = Object.keys(update);
key.forEach((k) => {
if(typeof update[key] == "object"){
this[k].deepUpdate(update[key], this[k])
}
else
this[k] = update[k]
})
}
init.deepUpdate({abc: {c: {l: 10}}})
console.log(init)
但请确保它会更改原始对象，您可以使其不更改原始对象：
JSON.parse(JSON.stringify(init)).deepUpdate({abc: {c: {l: 10}}})
这是使用 ES 12 的解决方案
function set(obj = {}, key, val) {
const keys = key.split('.')
const last = keys.pop()
keys.reduce((o, k) => o[k] ??= {}, obj)[last] = val
}
（对于旧版本的 javascript，您可以在 reduce 中执行o[k] || o[k] = {}代替）
首先，我们将keys设置为除最后一个键之外的所有内容的数组。
然后在reduce中，累加器每次都深入obj ，如果未定义该键的值，则将其初始化为空对象。
最后，我们将最后一个键的值设置为val 。
改进 bpmason1 的回答：-添加了一个 get() 函数。 - 不需要定义全局存储对象 - 可以从同域 iFrame 访问
function set(path, value)
{
var schema = parent.document;
path="data."+path;
var pList = path.split('.');
var len = pList.length;
for(var i = 0; i < len-1; i++)
{
if(!schema[pList[i]])
schema[pList[i]] = {}
schema = schema[pList[i]];
}
schema[pList[len-1]] = value;
}
function get(path)
{
path="data."+path;
var schema=parent.document;
var pList = path.split('.');
for(var i = 0; i < pList.length; i++)
schema = schema[pList[i]];
return schema;
}
set('mongo.db.user', 'root');
set('mongo.db.name', 'glen');
console.log(get('mongo.db.name')); //prints 'glen'
作为@aheuermann sed，您可以使用来自lodash库的set ，
但是，如果您出于某种原因不想将lodash添加到项目中，则可以使用递归 function 设置/覆盖 object 中的值。
/** * recursion function that called in main function * @param obj initial JSON * @param keysList array of keys * @param value value that you want to set * @returns final JSON */ function recursionSet(obj, keysList, value) { const key = keysList[0] if (keysList.length === 1) return {...obj, [key]: value } return {...obj, [key]: (recursionSet(obj?.[key] || {}, keysList.slice(1), value)) } } /** * main function that you can call for set a value in an object by nested keys * @param obj initial JSON * @param keysString nested keys that seprated by "." * @param value value that you want to set * @returns final JSON */ function objectSet(obj, keysString, value) { return recursionSet(obj, keysString.split('.'), value) } // simple usage const a1 = {} console.log('simple usage:', objectSet(a1, "b.c.d", 5)) // keep the initial data const a2 = {b:{e: 8}} console.log('keep the initial data:', objectSet(a2, "b.c.d", 5)) // override data const a3 = {b:{e: 8, c:2}} console.log('override data:', objectSet(a3, "b.c.d", 5)) // complex value const a4 = {b:{e: 8, c:2}} console.log('complex value:', objectSet(a4, "b.c.d", {f:12}))
有时，如果键也有点 (.)，它的字符串可能会造成问题。 因为即使是那个单一的键现在也会被分成不同的键。
最好将键路径存储在数组中，如下所示：['db','mongodb','user'] 并使用下面的 function 动态分配值。
function set(obj, path, value) {
var schema = obj;
var pList = path.slice();
var len = pList.length;
for (var i = 0; i < len - 1; i++) {
var elem = pList[i];
if (!schema[elem]) schema[elem] = {};
schema = schema[elem];
}
schema[pList[len - 1]] = value;
}
let path = ['db','mongodb','user'];
set(obj, path, 'root');
动态设置嵌套对象的属性（如果存在）。 重新创建 _.extend
[英]Dynamically set property of nested object if they exist. Recreate _.extend
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