diff --git a/docs/typescript/design.md b/docs/typescript/design.md index 9ffbe85ad7f..7c449ebc234 100644 --- a/docs/typescript/design.md +++ b/docs/typescript/design.md @@ -25,6 +25,11 @@ Use [caniuse.com](https://caniuse.com) to determine whether you can use a given {% include requirement/MUST id="ts-support-ts" %} compile without errors on TypeScript v3.5 and greater. +Supporting older versions of TypeScript can be a challenge. There are two general approaches: + +1. Don't use new features. +2. Use [`typesVersions`](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-1.html#version-selection-with-typesversions), which might require manual effort to produce typings compatible with older versions based on the new typings. Much of that effort can be automated using [`downlevel-dts`](https://github.com/sandersn/downlevel-dts). + {% include requirement/MUST id="ts-register-dropped-platforms" %} get approval from the [Architecture Board] to drop support for any platform (except IE11 and Node 6) even if support isn't required. ## Namespaces, NPM Scopes, and Distribution Tags {#ts-namespace}