Determine whether an array contains a value [duplicate]

Answer 1

Using array .map function that executes a function for every value in an array seems cleanest to me.

Ref: Array.prototype.map()

This method can work well both for simple arrays and for arrays of objects where you need to see if a key/value exists in an array of objects.

function inArray(myArray,myValue){
    var inArray = false;
    myArray.map(function(key){
        if (key === myValue){
            inArray=true;
        }
    });
    return inArray;
};

var anArray = [2,4,6,8]
console.log(inArray(anArray, 8)); // returns true
console.log(inArray(anArray, 1)); // returns false

function inArrayOfObjects(myArray,myValue,objElement){
    var inArray = false;
    myArray.map(function(arrayObj){
        if (arrayObj[objElement] === myValue) {
            inArray=true;
        }
    });
    return inArray;
};

var objArray = [{id:4,value:'foo'},{id:5,value:'bar'}]
console.log(inArrayOfObjects(objArray, 4, 'id')); // returns true
console.log(inArrayOfObjects(objArray, 'bar', 'value')); // returns true
console.log(inArrayOfObjects(objArray, 1, 'id')); // returns false