TSDocTypeScript has a way to describe objects which have unknown keys but known values on an object, via index signatures.
ts
interface EnvironmentVars {
NAME: string;
OS: string;
// Unknown properties are covered by this index signature.
[propName: string]: string;
}
declare const env: EnvironmentVars;
// Declared as existing
const sysName = env.NAME;
const os = env.OS;
// ^?
// Not declared, but because of the index
// signature, then it is considered a string
const nodeEnv = env.NODE_ENV;
// ^?interface EnvironmentVars {
NAME: string;
OS: string;
// Unknown properties are covered by this index signature.
[propName: string]: string;
}
declare const env: EnvironmentVars;
// Declared as existing
const sysName = env.NAME;
const os = env.OS;
// ^?
// Not declared, but because of the index
// signature, then it is considered a string
const nodeEnv = env.NODE_ENV;
// ^?Turning on noUncheckedIndexedAccess will add undefined to any un-declared field in the type.
ts
interface EnvironmentVars {
NAME: string;
OS: string;
// Unknown properties are covered by this index signature.
[propName: string]: string;
}
// @noUncheckedIndexedAccess
// ---cut---
declare const env: EnvironmentVars;
// Declared as existing
const sysName = env.NAME;
const os = env.OS;
// ^?
// Not declared, but because of the index
// signature, then it is considered a string
const nodeEnv = env.NODE_ENV;
// ^?interface EnvironmentVars {
NAME: string;
OS: string;
// Unknown properties are covered by this index signature.
[propName: string]: string;
}
// @noUncheckedIndexedAccess
// ---cut---
declare const env: EnvironmentVars;
// Declared as existing
const sysName = env.NAME;
const os = env.OS;
// ^?
// Not declared, but because of the index
// signature, then it is considered a string
const nodeEnv = env.NODE_ENV;
// ^?