mapValues.js
function addOperator(obj, field, operator, operand) {
    if(obj[field] === undefined) {
        obj[field] = {}
    }

    obj[field][operator] = operand
}
function addOperator(obj, field, operator, operand) {
    if(obj[field] === undefined) {
        obj[field] = {}
    }

    obj[field][operator] = operand
}
function addOperator ( obj , field , operator , operand ) { if ( obj [ field ] === undefined ) { obj [ field ] = { } } obj [ field ] [ operator ] = operand }
adds an operator to a field, handling the case where there is already another operator there
adds an operator to a field handling the case where there is already another operator there