Convert JavaScript string in dot notation into an object reference

Question

Given a JS object

var obj = { a: { b: \'1\', c: \'2\' } }

and a string

\"a.b\"

how can I convert the stri

Answer 1

You can obtain value of an object member by dot notation with a single line of code:

new Function('_', 'return _.' + path)(obj);

In you case:

var obj = { a: { b: '1', c: '2' } }
var val = new Function('_', 'return _.a.b')(obj);

To make it simple you may write a function like this:

function objGet(obj, path){
    return new Function('_', 'return _.' + path)(obj);
}

Explanation:

The Function constructor creates a new Function object. In JavaScript every function is actually a Function object. Syntax to create a function explicitly with Function constructor is:

new Function ([arg1[, arg2[, ...argN]],] functionBody)

where arguments(arg1 to argN) must be a string that corresponds to a valid javaScript identifier and functionBody is a string containing the javaScript statements comprising the function definition.

In our case we take the advantage of string function body to retrieve object member with dot notation.

Hope it helps.