How to fix "Initializer provides no value for this binding element and the binding element has no default value." in TypeScript?

Question

I am migrating Apollo GraphQL API project written in JavaScript to TypeScript. And I am having an error at finding a user code block, saying that var idArg: any Initializer provides no value for this binding element and the binding element has no default value.ts(2525)

  async findOne({ id: idArg } = {}) {
     // Red line here ^^^^^
    const user = await this.knex('users')
      .where('id', idArg)
      .first();

    if (!user) return;
    return user;
  }

Currently I added any to it without really knowing the actual solution, and the warning is gone.

  async findOne({ id: idArg }: any = {}) {
    const user = await this.knex('users')
      .where('id', idArg)
      .first();

    if (!user) return;
    return user;
  }

However I'd still like to know the actual solution. Should I add number type instead of any? But when I do that, error is Type '{}' is not assignable to type 'number'.ts(2322).

Please help.

Answer 1

Depending on what you want to accomplish there are a lot of ways in which you can solve this issue.

// The compiler checks the object { id: '1' } and it knows it has an id property
var { id } = { id: '1' }

/* The compiler is confused. It check the object {} and it knows it doesn't have 
a property id1, so it is telling you it doesn't know where to get the value 
for id1
*/
var { id1 } = {}

/* In this case the compiler knows the object doesn't have the property id2 but
since you provided a default value it uses it 'default value'.
 */
var { id2 = 'default value' } = {}

/* In your case there are a couple of solutions: */

// 1) Provide the value in the initializer
function findOne({ id: idArg } = { id: 'value here' }) {
    console.log(id)
}
findOne()

// 2) Provide a default value
function findOne1({ id: idArg = 'value here 1' } = {}) {}

// 3) Provide initializer and type definition
function findOne2({ id: idArg}: { id?: number } = {}) {}

// 3) Do not provide initializer
function findOne3({ id: idArg}: { id: number }) {}

Typescript playground link.