index.js
function getAllKeys(forValue, inObject) {
    var keys = []
    for (let key of Object.keys(inObject)) {
        if (inObject[key] === forValue) {
            keys.push(key)
        }
    }
    return keys
}
function getAllKeys(forValue, inObject) {
    var keys = []
    for (let key of Object.keys(inObject)) {
        if (inObject[key] === forValue) {
            keys.push(key)
        }
    }
    return keys
}
function getAllKeys

@param {*} forValue The value that has multiple keys
@param {Object} inObject The object under inspection
@returns {Array} Returns keys in an array

@example

getAllKeysFor('faf', { 'f':'faf', 'fa': 'faf', 'faf': 'faf', 'fafa':'fafa'})
returns: ["f", "fa", "faf"]