# TypeScript

This section provides TypeScript-specific tips & tricks for you to make the best out of the ecosystem.

## Strict mode

The `--strict` compiler flag was introduced in TypeScript 2.3 which activates TypeScript's "strict mode". The strict mode sets all strict typechecking options to `true` by default.

As of TypeScript 2.6, the affected options are:

* `--noImplicitAny`
* `--noImplicitThis`
* `--alwaysStrict`
* `--strictNullChecks`
* `--strictFunctionTypes`

Starting from version 2.0 of the starter kit, we've enabled the `--strict` flag in `tsconfig.json`. If this gives you compile time errors, you can try setting `"strict"` to `false`, or by overriding one or more of the options listed above.

**For more info:** https://blog.mariusschulz.com/2017/06/09/typescript-2-3-the-strict-compiler-option

## TSLint

TSLint checks your TypeScript code for readability, maintainability, and functionality errors, and can also enforce coding style standards.

This project provides TSLint rules through a `tslint.json` file, which extends the recommended rules from TSLint defined [here](https://github.com/palantir/tslint/blob/next/src/configs/recommended.ts).

We've made some changes to these rules, which we considered necessary and/or relevant to a proper Screeps project:

 - set the [forin](http://palantir.github.io/tslint/rules/forin/) rule to `false`, it was forcing `for ( ... in ...)` loops to check if object members were not coming from the class prototype.
 - set the [interface-name](http://palantir.github.io/tslint/rules/interface-name/) rule to `false`, in order to allow interfaces that are not prefixed with `I`.
 - set the [no-console](http://palantir.github.io/tslint/rules/no-console/) rule to `false`, in order to allow using `console`.
 - in the [variable-name](http://palantir.github.io/tslint/rules/variable-name/) rule, added `allow-leading-underscore`.

### Customising TSLint

You can also customise your `tslint.json` file to match the preferences of your codebase. Click [here](https://palantir.github.io/tslint/usage/configuration/), to find out how, and click [here](https://palantir.github.io/tslint/rules/) for a complete list of rules available.

If you believe that some rules should not apply to a part of your code (e.g. for one-off cases like having to use `require()` to include a module), you can use flags to let TSLint know about it: https://palantir.github.io/tslint/usage/rule-flags/

**More info about TSLint:** https://palantir.github.io/tslint/