check value in object array javascript code example

Example 1: check if object is present in array javascript

//Use something like this:

function containsObject(obj, list) {
    var i;
    for (i = 0; i < list.length; i++) {
        if (list[i] === obj) {
            return true;
        }
    }

    return false;
}

//In this case, containsObject(car4, carBrands) is true. Remove the carBrands.push(car4); call and it will return false instead. If you later expand to using objects to store these other car objects instead of using arrays, you could use something like this instead:

function containsObject(obj, list) {
    var x;
    for (x in list) {
        if (list.hasOwnProperty(x) && list[x] === obj) {
            return true;
        }
    }

    return false;
}

Example 2: check object in array javascript

var obj = {a: 5};
var array = [obj, "string", 5]; // Must be same object
array.indexOf(obj) !== -1 // True

Example 3: react array if id is present do not add element

addPerson = (person) => {
    let filteredPerson = this.state.likes.filter(like => like.name !== person.name);
    this.setState({
      likes: [...filteredPerson, person]
    })        
  }