Given a JS object
var obj = { a: { b: \'1\', c: \'2\' } }
and a string
\"a.b\"
how can I convert the stri
Using object-scan seems a bit overkill, but you can simply do
const objectScan = require('object-scan');
const get = (obj, p) => objectScan([p], { abort: true, rtn: 'value' })(obj);
const obj = { a: { b: '1', c: '2' } };
console.log(get(obj, 'a.b'));
// => 1
console.log(get(obj, '*.c'));
// => 2
There are a lot more advanced examples in the readme.
It's not clear what your question is. Given your object, obj.a.b
would give you "2" just as it is. If you wanted to manipulate the string to use brackets, you could do this:
var s = 'a.b';
s = 'obj["' + s.replace(/\./g, '"]["') + '"]';
alert(s); // displays obj["a"]["b"]
you could also use lodash.get
You just install this package (npm i --save lodash.get) and then use it like this:
const get = require('lodash.get');
const myObj = { user: { firstName: 'Stacky', lastName: 'Overflowy' }, id: 123 };
console.log(get(myObj, 'user.firstName')); // prints Stacky
console.log(get(myObj, 'id')); //prints 123
//You can also update values
get(myObj, 'user').firstName = John;
This is my extended solution proposed by: ninjagecko
For me simple string notation was not enough, so below version supports things like:
index(obj, 'data.accounts[0].address[0].postcode');
/**
* Get object by index
* @supported
* - arrays supported
* - array indexes supported
* @not-supported
* - multiple arrays
* @issues:
* index(myAccount, 'accounts[0].address[0].id') - works fine
* index(myAccount, 'accounts[].address[0].id') - doesnt work
* @Example:
* index(obj, 'data.accounts[].id') => returns array of id's
* index(obj, 'data.accounts[0].id') => returns id of 0 element from array
* index(obj, 'data.accounts[0].addresses.list[0].id') => error
* @param obj
* @param path
* @returns {any}
*/
var index = function(obj, path, isArray?, arrIndex?){
// is an array
if(typeof isArray === 'undefined') isArray = false;
// array index,
// if null, will take all indexes
if(typeof arrIndex === 'undefined') arrIndex = null;
var _arrIndex = null;
var reduceArrayTag = function(i, subArrIndex){
return i.replace(/(\[)([\d]{0,})(\])/, (i) => {
var tmp = i.match(/(\[)([\d]{0,})(\])/);
isArray = true;
if(subArrIndex){
_arrIndex = (tmp[2] !== '') ? tmp[2] : null;
}else{
arrIndex = (tmp[2] !== '') ? tmp[2] : null;
}
return '';
});
}
function byIndex(obj, i) {
// if is an array
if(isArray){
isArray = false;
i = reduceArrayTag(i, true);
// if array index is null,
// return an array of with values from every index
if(!arrIndex){
var arrValues = [];
_.forEach(obj, (el) => {
arrValues.push(index(el, i, isArray, arrIndex));
})
return arrValues;
}
// if array index is specified
var value = obj[arrIndex][i];
if(isArray){
arrIndex = _arrIndex;
}else{
arrIndex = null;
}
return value;
}else{
// remove [] from notation,
// if [] has been removed, check the index of array
i = reduceArrayTag(i, false);
return obj[i]
}
}
// reduce with byIndex method
return path.split('.').reduce(byIndex, obj)
}
here's my 10 cents to case, bellow function will get/set based on path provided,..
sure u can improve it, remove || and replace it with Object.hasOwnProperty
if you do care about false values mistakenly,
i tested it with a.b.c
and a.b.2.c {a:{b:[0,1,{c:7}]}}
and its works for both setting and getting :).
cheerz
function helper(obj, path, setValue){
const l = String(path).split('.');
return l.reduce((o,i, idx)=>{
if( l.length-idx===1) { o[i] = setValue || o[i];return setValue ? obj : o[i];}
o[i] = o[i] || {};
return o[i];
}, x)
}
If you wish to convert any object that contains dot notation keys into an arrayed version of those keys you can use this.
This will convert something like
{
name: 'Andy',
brothers.0: 'Bob'
brothers.1: 'Steve'
brothers.2: 'Jack'
sisters.0: 'Sally'
}
to
{
name: 'Andy',
brothers: ['Bob', 'Steve', 'Jack']
sisters: ['Sally']
}
convertDotNotationToArray(objectWithDotNotation) {
Object.entries(objectWithDotNotation).forEach(([key, val]) => {
// Is the key of dot notation
if (key.includes('.')) {
const [name, index] = key.split('.');
// If you have not created an array version, create one
if (!objectWithDotNotation[name]) {
objectWithDotNotation[name] = new Array();
}
// Save the value in the newly created array at the specific index
objectWithDotNotation[name][index] = val;
// Delete the current dot notation key val
delete objectWithDotNotation[key];
}
});
}