Fixed some grammar

I'm trying to see if a value from my data matches against an array of values to return true or false.

Here is what I have come up with so far...

acceptedGrades = ['A1','A2','A3','B1','B2','B3','C1','C2','C3'];

this.state.isValidGrade = _.every(acceptedGrades, d => item.grade === value);

e.g. If item.grade returns A1 grade: 'A1' return true, if item.grade returns value not in acceptedGrades return false.

I used the same statement to search for a property with hasOwnProperty and thats fine just need to look for the value of a property.

Can use lodash library.

Solution

There's a couple of ways to handle that. I think you're after find, filter, includes or findIndex. every wouldn't be a good fit here because it's evaluating the whole array to make sure all values satisfy your condition. I think you're just trying to match the grade to an item in the array if I'm understanding correctly.

const acceptedGrades = ['A1','A2','A3','B1','B2','B3','C1','C2','C3'];

// Get first match:
console.log(acceptedGrades.find( g => g === 'B2')); // returns 'B2'

// Get All Matches:
console.log(acceptedGrades.filter( g => g === 'B2')); // returns ['B2']

// Get Index of first match:
console.log(acceptedGrades.findIndex( g => g === 'B2' )); // returns 4

// See if array 'includes' the value
console.log(acceptedGrades.includes('B2')); // returns true