function ensureArrayAndPush(object, key, value) {
            if (!Array.isArray(object[key])) {
                object[key] = [];
            }
            object[key].push(value);
        }
function ensureArrayAndPush(object, key, value) {
            if (!Array.isArray(object[key])) {
                object[key] = [];
            }
            object[key].push(value);
        }
function ensureArrayAndPush ( object , key , value ) { if ( ! Array . isArray ( object [ key ] ) ) { object [ key ] = [ ] ; } object [ key ] . push ( value ) ; }
Ensure that an array exists at [key] on `object`, and add `value` to it.

@param {Object} object the object to mutate
@param {string} key the object's key
@param {*} value the value to add
@returns {void}
@private
Ensure that an array exists at [ key ] on object and add value to it .
Ensure an array is present