//You need to make the object first, then use [] to set it. var key = "happyCount"; var obj = {}; obj[key] = someValueArray; myArray.push(obj);
//For ES6 and Babel { [yourKeyVariable]: "yourValue", } // ES5 Alternative // Create the object first, then use [] to set your variable as a key var yourObject = {}; yourObject[yourKeyVariable] = "yourValue";