Let's say I have a complex object with properties that have properties.
var x = {};
x.A.B = 'Hello';
x.A.C = 'World!';
x.D.E = 100;
x.D.F = 2.5;
Is there anything I could put in a single set of square brackets in order to get back any of these properties? A simple test shows that x['A.B'] does not return 'Hello'. Is there any syntax for doing this?
If you don't want to iterate you could do it fairly safe with eval in strict mode. Not that I recommend doing this. But it's a way to do it.
var x = {A:{}};
x.A.B = 'Hello';
var propertyPath = 'A.B';
var value = eval('"use strict"; x.' + propertyPath);
console.log(value);
Another more reusable way would be to create a new Function object instead of using eval.
function propertyValue(obj, propertyPath) {
'use strict';
return (new Function('obj', 'return obj.' + propertyPath))(obj);
}
var value = propertyValue(x, 'A.B');
It is practically the same but has a clear definition.
propertyPath is coming from attributes on HTML controls that way the controls can indicate what properties their values will go in to (since we're not using any data binding library). They might be properties for properties.
deepProperyExists('a.b.c', obj)Just iterate over the number of periods and checking if the property is undefined each iteration. (a, a.b, a.b.c)