Access JavaScript property case-insensitively?

Question

Assume I have an object:

var obj = {   foo:"bar",   fizz:"buzz" }; 

I need to access a property of that object dynamically like so:

var objSetter = function(prop,val){   obj[prop] = val; } 

No problems there, except for that prop needs to be case insensitive in case the property name is passed into the function as, say, Foo instead of foo.

So how can I point to an object's property by name without regard to case? I would like to avoid iterating the entire object if possible.

Answer 1

Try this:

var myObject = { "mIxeDCaSEKeY": "value" };  var searchKey = 'mixedCaseKey'; var asLowercase = searchKey.toLowerCase(); myObject[Object.keys(myObject).find(key => key.toLowerCase() === asLowercase)]; 

You can alternatively already provide the searchKey in lowercase.

If you want it as a function:

/**   * @param {Object} object   * @param {string} key   * @return {any} value  */ function getParameterCaseInsensitive(object, key) {   const asLowercase = key.toLowercase();   return object[Object.keys(object)     .find(k => k.toLowerCase() === asLowercase)   ]; } 

If the object can't be found, then it'll return undefined, just like normal.

If you need to support older browsers, then you can use filter instead:

function getParameterCaseInsensitive(object, key) {   const asLowercase = key.toLowercase();   return object[Object.keys(object).filter(function(k) {     return k.toLowerCase() === asLowercase;   })[0]]; } 

I suggest using the polyfills for Object.keys() and Array.filter() if you need even older support.