How to use string as a key to update object

How to use string as a key to update object - javascript

I am trying to create a function that accepts the path in an object and makes that the key.
for example, if I wanted to update the city, which is is a child object of a company, which is a child object of a property I could do something like this:
originalObj['property']['company']['city'] = test
Here is my code so far:
function updateObj(path, value){
let valuePath = path.split(',')
let key=''
for(let i=0; i<valuePath.length ; i++){
key = key+`[valuePath[${i}]]`
}
//key = [valuePath[0]] [valuePath[1]] [valuePath[2]]
originalObj[key] = value
}
setObj('property,company,city', test)

You could save the last key of the path and use a temporary object for getting the final object for assigning the value.
function updateObj(path, value) {
var valuePath = path.split(','),
last = valuePath.pop(),
temp = object;
for (let i = 0; i < valuePath.length; i++) {
temp = temp[valuePath[i]];
}
temp[last] = value;
}
var object = { property: { company: { city: 'London' } } };
updateObj('property,company,city', 'New York');
console.log(object);
With Array#reduce
function updateObj(path, value) {
var valuePath = path.split(','),
last = valuePath.pop();
valuePath.reduce((o, k) => o[k] = o[k] || {}, object)[last] = value;
}
var object = {};
updateObj('property,company,city', 'New York');
console.log(object);

function updateObj(obj, path, value){
path.split(",").slice(0,-1).reduce((obj, key) => obj[key] || (obj[key] = {}), obj)[path.split(",").pop()] = value;
}

Try this:
function setObj(originalObj, path, value){
var parts = path.split(',');
var lastKey = parts.pop();
var obj = originalObj;
parts.forEach(
function(key) {
key = key.trim();
obj[key] = obj[key] || {};
obj = obj[key];
}
);
obj[lastKey] = value;
}
var originalObj = {};
var test = "This is a test";
setObj(originalObj, 'property,company,city', test)
console.log(JSON.stringify(originalObj,0,2));
It walks through your list and creates sub objects for all but the last. It then uses the last as the key to store the value.
The advantage to this code is that you don't assume the original Object variable name. And, if you wanted it to be pure and not to affect the original object structure then you could make these minor changes:
function setObj(originalObj, path, value){
var parts = path.split(',');
var lastKey = parts.pop();
var newObj = Object.assign({}, originalObj);
var obj = newObj;
parts.forEach(
function(key) {
obj[key] = Object.assign({}, obj[key] || {});
obj = obj[key];
}
);
obj[lastKey] = value;
return newObj;
}
var originalObj = {animals: {dog:"bark",cat:"meow"},property:{company:{name:"Fred's Things"}}};
var test = "This is a test";
var result = setObj(originalObj, 'property,company,city', test)
console.log(JSON.stringify(originalObj,0,2));
console.log(JSON.stringify(result,0,2));

Related

Javascript json add a child element dynamically [duplicate]

Suppose we are only given
var obj = {};
var propName = "foo.bar.foobar";
How can we set the property obj.foo.bar.foobar to a certain value (say "hello world")?
So I want to achieve this, while we only have the property name in a string:
obj.foo.bar.foobar = "hello world";

function assign(obj, prop, value) {
if (typeof prop === "string")
prop = prop.split(".");
if (prop.length > 1) {
var e = prop.shift();
assign(obj[e] =
Object.prototype.toString.call(obj[e]) === "[object Object]"
? obj[e]
: {},
prop,
value);
} else
obj[prop[0]] = value;
}
var obj = {},
propName = "foo.bar.foobar";
assign(obj, propName, "Value");

I know it's an old one, but I see only custom functions in answers.
If you don't mind using a library, look at lodash _.set and _.get function.

Since this question appears to be answered by incorrect answers, I'll just refer to the correct answer from a similar question
function setDeepValue(obj, value, path) {
if (typeof path === "string") {
var path = path.split('.');
}
if(path.length > 1){
var p=path.shift();
if(obj[p]==null || typeof obj[p]!== 'object'){
obj[p] = {};
}
setDeepValue(obj[p], value, path);
}else{
obj[path[0]] = value;
}
}
Use:
var obj = {};
setDeepValue(obj, 'Hello World', 'foo.bar.foobar');

edit: I've created a jsPerf.com testcase to compare the accepted answer with my version.
Turns out that my version is faster, especially when you go very deep.
http://jsfiddle.net/9YMm8/
var nestedObjectAssignmentFor = function(obj, propString, value) {
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
tmpObj = tmpObj[propNames[i]] = i !== propLength ? {} : value;
}
return obj;
}
var obj = nestedObjectAssignment({},"foo.bar.foobar","hello world");

All solutions overid any of the original data when setting so I have tweaked with the following, made it into a single object too:
var obj = {}
nestObject.set(obj, "a.b", "foo");
nestObject.get(obj, "a.b"); // returns foo
var nestedObject = {
set: function(obj, propString, value) {
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
if (i === propLength){
if(tmpObj[propNames[i]]){
tmpObj[propNames[i]] = value;
}else{
tmpObj[propNames[i]] = value;
}
}else{
if(tmpObj[propNames[i]]){
tmpObj = tmpObj[propNames[i]];
}else{
tmpObj = tmpObj[propNames[i]] = {};
}
}
}
return obj;
},
get: function(obj, propString){
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
if(tmpObj[propNames[i]]){
tmpObj = tmpObj[propNames[i]];
}else{
break;
}
}
return tmpObj;
}
};
Can also change functions to be an Oject.prototype method changing obj param to this:
Object.prototype = { setNested = function(){ ... }, getNested = function(){ ... } }
{}.setNested('a.c','foo')

Here is a get and set function i just compiled from a couple of threads + some custom code.
It will also create keys that don't exist on set.
function setValue(object, path, value) {
var a = path.split('.');
var o = object;
for (var i = 0; i < a.length - 1; i++) {
var n = a[i];
if (n in o) {
o = o[n];
} else {
o[n] = {};
o = o[n];
}
}
o[a[a.length - 1]] = value;
}
function getValue(object, path) {
var o = object;
path = path.replace(/\[(\w+)\]/g, '.$1');
path = path.replace(/^\./, '');
var a = path.split('.');
while (a.length) {
var n = a.shift();
if (n in o) {
o = o[n];
} else {
return;
}
}
return o;
}

Here is a simple function to do that using reference.
function setValueByPath (obj, path, value) {
var ref = obj;
path.split('.').forEach(function (key, index, arr) {
ref = ref[key] = index === arr.length - 1 ? value : {};
});
return obj;
}

You could split the path and make a check if the following element exist. If not assign an object to the new property.
Return then the value of the property.
At the end assign the value.
function setValue(object, path, value) {
var fullPath = path.split('.'),
way = fullPath.slice(),
last = way.pop();
way.reduce(function (r, a) {
return r[a] = r[a] || {};
}, object)[last] = value;
}
var object = {},
propName = 'foo.bar.foobar',
value = 'hello world';
setValue(object, propName, value);
console.log(object);

Here's one that returns the updated object
function deepUpdate(value, path, tree, branch = tree) {
const last = path.length === 1;
branch[path[0]] = last ? value : branch[path[0]];
return last ? tree : deepUpdate(value, path.slice(1), tree, branch[path[0]]);
}
const path = 'cat.dog';
const updated = deepUpdate('a', path.split('.'), {cat: {dog: null}})
// => { cat: {dog: 'a'} }

A very straightforward one.
This implementation should be very performant.
It avoids recursions, and function calls, while maintaining simplicity.
/**
* Set the value of a deep property, creating new objects as necessary.
* #param {Object} obj The object to set the value on.
* #param {String|String[]} path The property to set.
* #param {*} value The value to set.
* #return {Object} The object at the end of the path.
* #author github.com/victornpb
* #see https://stackoverflow.com/a/46060952/938822
* #example
* setDeep(obj, 'foo.bar.baz', 'quux');
*/
function setDeep(obj, path, value) {
const props = typeof path === 'string' ? path.split('.') : path;
for (var i = 0, n = props.length - 1; i < n; ++i) {
obj = obj[props[i]] = obj[props[i]] || {};
}
obj[props[i]] = value;
return obj;
}
/*********************** EXAMPLE ***********************/
const obj = {
hello : 'world',
};
setDeep(obj, 'root', true);
setDeep(obj, 'foo.bar.baz', 1);
setDeep(obj, ['foo','quux'], '😉');
console.log(obj);
// ⬇︎ Click "Run" below to see output

I was looking for an answer that does not overwrite existing values and was easily readable and was able to come up with this. Leaving this here in case it helps others with the same needs
function setValueAtObjectPath(obj, pathString, newValue) {
// create an array (pathComponents) of the period-separated path components from pathString
var pathComponents = pathString.split('.');
// create a object (tmpObj) that references the memory of obj
var tmpObj = obj;
for (var i = 0; i < pathComponents.length; i++) {
// if not on the last path component, then set the tmpObj as the value at this pathComponent
if (i !== pathComponents.length-1) {
// set tmpObj[pathComponents[i]] equal to an object of it's own value
tmpObj[pathComponents[i]] = {...tmpObj[pathComponents[i]]}
// set tmpObj to reference tmpObj[pathComponents[i]]
tmpObj = tmpObj[pathComponents[i]]
// else (IS the last path component), then set the value at this pathComponent equal to newValue
} else {
// set tmpObj[pathComponents[i]] equal to newValue
tmpObj[pathComponents[i]] = newValue
}
}
// return your object
return obj
}

Same as Rbar's answers, very useful when you're working with redux reducers. I use lodash clone instead of spread operator to support arrays too:
export function cloneAndPatch(obj, path, newValue, separator='.') {
let stack = Array.isArray(path) ? path : path.split(separator);
let newObj = _.clone(obj);
obj = newObj;
while (stack.length > 1) {
let property = stack.shift();
let sub = _.clone(obj[property]);
obj[property] = sub;
obj = sub;
}
obj[stack.shift()] = newValue;
return newObj;
}

Object.getPath = function(o, s) {
s = s.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
s = s.replace(/^\./, ''); // strip a leading dot
var a = s.split('.');
for (var i = 0, n = a.length; i < n; ++i) {
var k = a[i];
if (k in o) {
o = o[k];
} else {
return;
}
}
return o;
};
Object.setPath = function(o, p, v) {
var a = p.split('.');
var o = o;
for (var i = 0; i < a.length - 1; i++) {
if (a[i].indexOf('[') === -1) {
var n = a[i];
if (n in o) {
o = o[n];
} else {
o[n] = {};
o = o[n];
}
} else {
// Not totaly optimised
var ix = a[i].match(/\[.*?\]/g)[0];
var n = a[i].replace(ix, '');
o = o[n][ix.substr(1,ix.length-2)]
}
}
if (a[a.length - 1].indexOf('[') === -1) {
o[a[a.length - 1]] = v;
} else {
var ix = a[a.length - 1].match(/\[.*?\]/g)[0];
var n = a[a.length - 1].replace(ix, '');
o[n][ix.substr(1,ix.length-2)] = v;
}
};

Here's a simple method that uses a scoped Object that recursively set's the correct prop by path.
function setObjectValueByPath(pathScope, value, obj) {
const pathStrings = pathScope.split('/');
obj[pathStrings[0]] = pathStrings.length > 1 ?
setObjectValueByPath(
pathStrings.splice(1, pathStrings.length).join('/'),
value,
obj[pathStrings[0]]
) :
value;
return obj;
}

How about a simple and short one?
Object.assign(this.origin, { [propName]: value })

You can use reduce : (you can test it by copy/paste on browser console)
const setValueOf = (obj, value, ...path) => {
path.reduce((o, level, idx) => {
if(idx === path.length -1) { o[level] = value }; // on last change the value of the prop
return o && o[level]; // return the prop
}, obj);
};
Example
let objExmp = {a: 'a', b: {b1: 'b1', b2: 'b2', b3: { b3_3 : 'default_value' } }};
setValueOf(objExmp, 'new_value' , 'b', 'b3', 'b3_3');
console.log('objExmp', objExmp); // prop changed to 'new_value'
You can split the string path by '.' and spread like :
setValueOf(objExmp, 'new_value' , ...'b.b3.b3_3'.split('.'));

JavaScript: Convert dot notation string to array [duplicate]

I'm trying to create a JS object dynamically providing a key and a value. The key is in dot notation, so if a string like car.model.color is provided the generated object would be:
{
car: {
model: {
color: value;
}
}
}
The problem has a trivial solution if the key provided is a simple property, but i'm struggling to make it work for composed keys.
My code:
function (key, value) {
var object = {};
var arr = key.split('.');
for(var i = 0; i < arr.length; i++) {
object = object[arr[i]] = {};
}
object[arr[arr.length-1]] = value;
return object;
}

your slightly modified code
function f(key, value) {
var result = object = {};
var arr = key.split('.');
for(var i = 0; i < arr.length-1; i++) {
object = object[arr[i]] = {};
}
object[arr[arr.length-1]] = value;
return result;
}
In the loop you should set all of the props but the last one.
Next set the final property and all set.

If you're using lodash you could use _.set(object, path, value)
const obj = {}
_.set(obj, "car.model.color", "my value")
console.log(obj)
<script src="https://cdn.jsdelivr.net/npm/lodash#4.17.15/lodash.min.js"></script>

Use namespace pattern, like the one Addy Osmani shows: http://addyosmani.com/blog/essential-js-namespacing/
Here's the code, pasted for convenience, all credit goes to Addy:
// top-level namespace being assigned an object literal
var myApp = myApp || {};
// a convenience function for parsing string namespaces and
// automatically generating nested namespaces
function extend( ns, ns_string ) {
var parts = ns_string.split('.'),
parent = ns,
pl, i;
if (parts[0] == "myApp") {
parts = parts.slice(1);
}
pl = parts.length;
for (i = 0; i < pl; i++) {
//create a property if it doesnt exist
if (typeof parent[parts[i]] == 'undefined') {
parent[parts[i]] = {};
}
parent = parent[parts[i]];
}
return parent;
}
// sample usage:
// extend myApp with a deeply nested namespace
var mod = extend(myApp, 'myApp.modules.module2');

function strToObj(str, val) {
var i, obj = {}, strarr = str.split(".");
var x = obj;
for(i=0;i<strarr.length-1;i++) {
x = x[strarr[i]] = {};
}
x[strarr[i]] = val;
return obj;
}
usage: console.log(strToObj("car.model.color","value"));

I would use a recursive method.
var createObject = function(key, value) {
var obj = {};
var parts = key.split('.');
if(parts.length == 1) {
obj[parts[0]] = value;
} else if(parts.length > 1) {
// concat all but the first part of the key
var remainingParts = parts.slice(1,parts.length).join('.');
obj[parts[0]] = createObject(remainingParts, value);
}
return obj;
};
var simple = createObject('simple', 'value1');
var complex = createObject('more.complex.test', 'value2');
console.log(simple);
console.log(complex);
(check the console for the output)

Here's a recursive approach to the problem:
const strToObj = (parts, val) => {
if (!Array.isArray(parts)) {
parts = parts.split(".");
}
if (!parts.length) {
return val;
}
return {
[parts.shift()]: strToObj(parts, val)
};
}

Dynamic object creation from an array

I want to generate a dynamic object and assign value into it. Following is the code
var chunk = "INTERNATIONALISATION#LANGUAGE#DICTIONARY#EN";
var c = chunk.split('#');
var a = {};
So the output should be like this
a["INTERNATIONALISATION"]["LANGUAGE"]["DICTIONARY"]["EN"] = 10;
Tried looping through array but nothing works for now.Please advise.

Try this:
var chunk = "INTERNATIONALISATION#LANGUAGE#DICTIONARY#EN";
var c = chunk.split('#');
var a = {};
var lastKey = c.pop();
c.reduce((obj, key) => obj[key] = obj[key] || {}, a)[lastKey] = 10;
To make it more convenient you can put it in a function:
const dynamicAssign = (object, stringPath, value) => {
const path = stringPath.split('#');
const lastKey = path.pop();
const target = path.reduce((obj, key) => obj[key] = obj[key] || {}, object);
target[lastKey] = value;
};
const a = {};
dynamicAssign(a, "INTERNATIONALISATION#LANGUAGE#DICTIONARY#EN", 10);

Create nested object dynamically with forEach

I have an 'path' string: 'profile.name.en';
I want to use this to create an object dynamically. I'm using this function and its working:
function set(obj, path, value) {
var schema = obj; // a moving reference to internal objects within obj
var arr = path.split('.');
var len = arr.length;
for(var i = 0; i < len-1; i++) {
var elem = arr[i];
if( !schema[elem] ) schema[elem] = {};
schema = schema[elem];
}
schema[arr[len-1]] = value;
return schema;
}
Use it like this:
var a = {};
var path = 'profile.name.en';
var profileName = 'OleFrank';
var o = set(a, path, profileName);
// result
{
profile: {
name: {
en: 'OleFrank'
}
}
}
I tried to refactor to using forEach instead of for-loop, but then it's not working anymore. Why is this??

You could use Array#reduce, because this returns the object you need, without keeping a reference outside.
function set(object, path, value) {
var keys = path.split('.'),
last = keys.pop();
keys.reduce(function (o, k) {
return o[k] = o[k] || {};
}, object)[last] = value;
}
var a = {},
path = 'profile.name.en',
profileName = 'OleFrank';
set(a, path, profileName); // no need of an assignment, because of
// call by reference with an object
console.log(a);
Version with Array#forEach
function set(object, path, value) {
var keys = path.split('.'),
last = keys.pop();
keys.forEach(function (k) {
object[k] = object[k] || {};
object = object[k];
});
object[last] = value;
}
var a = {},
path = 'profile.name.en',
profileName = 'OleFrank';
set(a, path, profileName);
console.log(a);

convert array to object javascript

I have the following array:
["recordList", "userList", "lastChanged"]
And I want something like this:
lastChangedValue = "231231443234";
var object = {};
object = {
recordList: {
userList: {
lastChanged: lastChangedValue
}
}
}
How I can do this?
Thanks in advance.

Try this:
var array = ["recordList", "userList", "lastChanged"];
var value = "231231443234";
function arrayToObject(array, object, value) {
var ref = object;
for (var i=0; i<array.length-1; ++i) {
if (!ref[array[i]]) {
ref[array[i]] = {};
}
ref = ref[array[i]]
}
ref[array[array.length-1]] = value;
return object;
}
alert(JSON.stringify(arrayToObject(array, {}, value)));

You can iterate through property names and create one nested level of new object in each iteration:
var props = ["recordList", "userList", "lastChanged"];
var lastChangedValue = "231231443234";
var obj = {}
var nested = obj;
props.forEach(function(o, i) {
nested[o] = i === props.length - 1 ? lastChangedValue : {};
nested = nested[o];
});
console.log(obj);

There are probably a bunch of ways to do it, one way is with reduce
var keys = ["recordList", "userList", "lastChanged"];
var temp = keys.slice().reverse(),
lastChangedValue = "231231443234";
var result = temp.reduce( function (obj, val, ind, arr) {
if (ind===0) {
obj[val] = lastChangedValue;
return obj;
} else {
var x = {};
x[val] = obj;
return x;
}
}, {});
console.log(result);

Solving with recursion
var fields = ["recordList", "userList", "lastChanged"];
lastChangedValue = "231231443234";
var object = {};
(function addFields(o, i, v) {
if (i == fields.length - 1) {
o[fields[i]] = v;
return;
}
o[fields[i]] = {};
addFields(o[fields[i]], ++i, v)
})(object, 0, lastChangedValue);
alert(JSON.stringify(object));

Develop Reference

JavaScript is the programming language of the Web.

How to use string as a key to update object - javascript

function updateObj(obj, path, value){ path.split(",").slice(0,-1).reduce((obj, key) => obj[key] || (obj[key] = {}), obj)[path.split(",").pop()] = value; }

Related

Javascript json add a child element dynamically [duplicate]

JavaScript: Convert dot notation string to array [duplicate]

Dynamic object creation from an array

Create nested object dynamically with forEach

convert array to object javascript

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