How to check if array contains specific object [duplicate]

问题

I am trying to check if array of objects contain a specific object or object with specific property.

var mainArray = [
{name:"Yahya", age:"29"},
{name:"Ahmed", age:"19"},
{name:"Mohamed", age:"10"},
{name:"Ali", age:"32"},
{name:"Mona", age:"25"},
{name:"Shady", age:"62"},
{name:"Reem", age:"11"},
{name:"Marwa", age:"52"}
]

var myObject = {name:"Yahya", age:"29"};

function check() {
if (mainArray.indexOf(myObject) > -1) {
  console.log("true")
  return true;
} else {
  console.log('false')
  return false;
}
};

<button onClick="check()">Check</button>

here's however the object is same as one of array objects . but it's return false . I tried includes, also not working.

回答1:

If you wish to check if the array of objects contain that specific object then you can use Array.some

var mainArray = [{
    name: "Yahya",
    age: "29"
  },
  {
    name: "Ahmed",
    age: "19"
  },
  {
    name: "Mohamed",
    age: "10"
  },
  {
    name: "Ali",
    age: "32"
  },
  {
    name: "Mona",
    age: "25"
  },
  {
    name: "Shady",
    age: "62"
  },
  {
    name: "Reem",
    age: "11"
  },
  {
    name: "Marwa",
    age: "52"
  }
]

var myObject = {
  name: "Yahya",
  age: "29"
};

let ans = mainArray.some(function(arrVal) {
  return myObject.name === arrVal.name;
});
console.log(ans)

You can also use filter method.In this case it will return an array of the matched elements. Check the length of the returned array to verify if it contains desired elements

var mainArray = [{
    name: "Yahya",
    age: "29"
  },
  {
    name: "Ahmed",
    age: "19"
  },
  {
    name: "Mohamed",
    age: "10"
  },
  {
    name: "Ali",
    age: "32"
  },
  {
    name: "Mona",
    age: "25"
  },
  {
    name: "Shady",
    age: "62"
  },
  {
    name: "Reem",
    age: "11"
  },
  {
    name: "Marwa",
    age: "52"
  }
]

var myObject = {
  name: "Yahya",
  age: "29"
};

let newAns = mainArray.filter(function(item) {
  return item.name === myObject.name && item.age === myObject.age
})
if (newAns.length > 0) {
  console.log(true);
} else {
  console.log(false)
}

回答2:

There is a Array method given by findIndex, we can do simply something like below

var mainArray = [
  {name:"Yahya", age:"29"},
  {name:"Ahmed", age:"19"},
  {name:"Mohamed", age:"10"},
  {name:"Ali", age:"32"},
  {name:"Mona", age:"25"},
  {name:"Shady", age:"62"},
  {name:"Reem", age:"11"},
  {name:"Marwa", age:"52"}
]

var myObject = {name:"Yahya", age:"29"};

function check() {
  if (mainArray.findIndex(obj => obj.name == myObject.name && obj.age == myObject.age) > -1) {
    console.log("true")
    return true;
  } else {
    console.log('false')
    return false;
  }
};

<button onClick="check()">Check</button>

回答3:

You can check if some elements of that array are the same as the object you are checking against when stringified, like so:

mainArray.some(e => JSON.stringify(e) === JSON.stringify(myObject))

function check() {
 console.log(mainArray.some(e => JSON.stringify(e) === JSON.stringify(myObject)))
};


let mainArray = [{
    name: "Yahya",
    age: "29"
  },
  {
    name: "Ahmed",
    age: "19"
  },
  {
    name: "Mohamed",
    age: "10"
  },
  {
    name: "Ali",
    age: "32"
  },
  {
    name: "Mona",
    age: "25"
  },
  {
    name: "Shady",
    age: "62"
  },
  {
    name: "Reem",
    age: "11"
  },
  {
    name: "Marwa",
    age: "52"
  }
]

let myObject = {
  name: "Yahya",
  age: "29"
};

<button onClick="check()">Check myObject</button>

回答4:

The indexOf will try to find the object in the collection using the basic comparison mechanism. Try to run: {name:"Yahya", age:"29"} === {name:"Yahya", age:"29"} in javascript console and you'll get false, since these are 2 different objects, created using the same string literals.

I believe you should read more info on Objects in OOP in general.

To check if a collection contains an element with the tester function provided use Array.prototype.some():

var mainArray = [
    {name:"Yahya", age:"29"},
    {name:"Ahmed", age:"19"},
    {name:"Mohamed", age:"10"},
    {name:"Ali", age:"32"},
    {name:"Mona", age:"25"},
    {name:"Shady", age:"62"},
    {name:"Reem", age:"11"},
    {name:"Marwa", age:"52"}
];

var myObject = {name: "Yahya", age: "29"};

function check(object) {
    return mainArray.some(function(element) {
        return element.name === object.name && element.age === object.age;
    })
}

console.log(check(myObject));

Notice that the comparison is done using "===", if you have age in your mainArray collection set as string and in myObject - as number, use "==" for age comparison instead.

来源：https://stackoverflow.com/questions/51695282/how-to-check-if-array-contains-specific-object

标签

javascript

arrays

javascript-objects

indexof