Array filtering in JavaScript is returning an empty array-CodePudding

// console.log("Testing Merging of data");

const Array_1 = [{ class_1: 4, HeadTeacher: "Mrs Joe" }];
const Array_2 = [{ class_1: 10, HeadTeacher: "Loveth" }];
const Array_3 = [{ class_1: 1, HeadTeacher: "Itunu" }];
const Array_4 = [{ class_1: 1, HeadTeacher: "John" }];

const result = [...Array_1, ...Array_2, ...Array_3];

const Final = result.filter((item, index) => {
  return item.class_1 === 10 && item.class_1 === 1;
});

console.log(Final);

//  Expected result
// [{ class_1: 1, HeadTeacher: "Itunu" }, { class_1: 1, HeadTeacher: "John" }; ];

// Out put ; Empty array []

I have an array of objects which I'm filtering to return certain results based on my filter criteria. but all I did was just returning an empty array.

CodePudding user response：

The reason why your array output is different from your expected result is your condition when returning.

You are using logical AND (&&). You should change && to ||.

CodePudding user response：

Use OR(||) operation instead of AND(&&).

Correct Code ->

const Array_1 = [{ class_1: 4, HeadTeacher: "Mrs Joe" }];
const Array_2 = [{ class_1: 10, HeadTeacher: "Loveth" }];
const Array_3 = [{ class_1: 1, HeadTeacher: "Itunu" }];
const Array_4 = [{ class_1: 1, HeadTeacher: "John" }];

const result = [...Array_1, ...Array_2, ...Array_3];

const Final = result.filter((item, index) => {
  return item.class_1 === 10 || item.class_1 === 1;
});

console.log(Final);