Create typeof.js

[34638a]

Add implementation of javascript "typeof".
Implementation is based on json.js call which will yield a inline string as a result.

Registration into helpers list is required if approved. https://github.com/bigcommerce/paper-handlebars/blob/master/helpers.js

What? Why?

Function to determine type of provided input regardless of what the inline result is for use in if statements, and inline object construction. eg. of using in JSON.Parse string {"value_type":"{{typeof variable}}"}.
This also has the side effect that it will prevent needed to serialise objects in no-js environments to determine flow state via CSS selectors.

[data-test-for-typeof="Number"] {
    display: hidden;
}

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/typeof

How was it tested?

Not tested. Based off existing file json.js with output line returning typeof data instead of JSON.stringify(data).

cc @bigcommerce/storefront-team