Function mapping

Mapping foreign key value to primary key value

This functionality is almost similar to mongodb lookup https://www.mongodb.com/docs/manual/reference/operator/aggregation/lookup/

Example: array of objects

const primaryArray = [
 { id: 1, userId: 1 },
 { id: 2, userId: 2 },
];
const userArray = [
 { id: 1, name: 'John' },
 { id: 2, name: 'Mary' },
];
const result = mapping(
 primaryArray,
 userArray,
 { foreignKey: 'id', primaryKey: 'userId', asField: 'user' },
);
expect(result).toEqual([
 { id: 1, user: { id: 1, name: 'John' }, userId: 1 },
 { id: 2, user: { id: 2, name: 'Mary' }, userId: 2 },
]);
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Example: array of objects with array of primary key

const primaryArray = [
 { id: 1, users: [1, 2] },
];
const userArray = [
 { id: 1, name: 'John' },
 { id: 2, name: 'Mary' },
];
const result = mapping(
 primaryArray,
 userArray,
 { foreignKey: 'id', primaryKey: 'users' },
);
expect(result).toEqual([
 { id: 1, users: [{ id: 1, name: 'John' }, { id: 2, name: 'Mary' }] },
]);
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Example: array of strings or numbers

const primaryArray = [1, 2];
const userArray = [
 { id: 1, name: 'John' },
 { id: 2, name: 'Mary' },
];
const result = mapping(
 primaryArray,
 userArray,
 { foreignKey: 'id' },
);
expect(result).toEqual([
 { id: 1, name: 'John' },
 { id: 2, name: 'Mary' },
]);
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