# js-typescript-guards

**Repository Path**: mirrors_googlemaps/js-typescript-guards

## Basic Information

- **Project Name**: js-typescript-guards
- **Description**:  TypeScript guards for the Google Maps JavaScript API.
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-11-12
- **Last Updated**: 2026-09-19

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Google Maps TypeScript Guards

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## Description

This package provides [TypeScript guards](https://www.typescriptlang.org/docs/handbook/2/narrowing.html#using-type-predicates) for the Google Maps JavaScript API. 

A type guard (or type predicate) is an expression that performs a runtime check that guarantees the type in some scope. Type guards are used to narrow the type of a variable or parameter.

## Documentation

For the complete API check the [reference documentation](https://googlemaps.github.io/js-typescript-guards/index.html).

## Install

Available via npm as the package [@googlemaps/typescript-guards](https://www.npmjs.com/package/@googlemaps/typescript-guards).

```sh
npm i @googlemaps/typescript-guards
```

## Example

The following example narrows a union type `google.maps.LatLng | google.maps.LatLngLiteral` to `google.maps.LatLngLiteral` using the `isLatLngLiteral` guard.

```typescript
import { isLatLngLiteral } from "@googlemaps/typescript-guards";

const latLng: google.maps.LatLng | google.maps.LatLngLiteral = ...;

if (isLatLngLiteral(latLng)) {
  lat = latLng.lat;
  lng = latLng.lng;
} else {
  lat = latLng.lat();
  lng = latLng.lng();
}
```