Basic Typescript Type Inference

inferred.ts

// basic type inference
function inferred() {
  const a = 'hi'
  return a
}

// inferred from interface definition
interface DefinesTypes {
  inferred: (first: number, second: string) => number
}

const f: DefinesTypes = {
  inferred(first, second) {
    return first + second.length
  }
}