First pass on style guide (denoland/deno_std#66)

Original: https://github.com/denoland/deno_std/commit/2916791dfb14bf486185eca6c7859b49c1c4c052

2 files changed, 111 insertions, 13 deletions

diff --git a/README.md b/README.md
index 999a09331..fce2c870f 100644
--- a/README.md
+++ b/README.md
@@ -2,37 +2,135 @@
 
 [![Build Status](https://dev.azure.com/denoland/deno_std/_apis/build/status/denoland.deno_std?branchName=master)](https://dev.azure.com/denoland/deno_std/_build/latest?definitionId=2?branchName=master)
 
-This repository contains collections of modules that create a standard library
-for Deno.
-
-* **[colors](./colors/)**
+- **[colors](./colors/)**
 
   Modules that generate ANSI color codes for the console.
 
-* **[flags](./flags/)**
+- **[flags](./flags/)**
 
   Command line arguments parser.
 
-* **[logging](./logging/)**
+- **[logging](./logging/)**
 
   Command line logging
 
-* **[mkdirp](./mkdirp/)**
+- **[mkdirp](./mkdirp/)**
 
-  Make directory branches. 
+  Make directory branches.
 
-* **[net](./net/)**
+- **[net](./net/)**
 
   A framework for creating HTTP/HTTPS servers inspired by GoLang.
 
-* **[path](./path/)**
+- **[path](./path/)**
 
   File path manipulation.
 
-* **[testing](./testing/)**
+- **[testing](./testing/)**
 
   Testing
 
+## Style Guide
+
+### Use the term "module" instead of "library" or "package"
+
+For clarity and consistency avoid the terms "library" and "package". Instead use
+"module" to refer to a single JS or TS file and also to refer to a directory of
+TS/JS code.
+
+### Use the filename "mod.ts" as the default entry point to a directory of code
+
+`index.ts` comes with the wrong connotations - and `main.ts` should be reserved
+for executable programs. The filename `mod.ts` follows Rust’s convention, is
+shorter than `index.ts`, and doesn’t come with any preconceived notions about
+how it might work.
+
+### Within `deno_std`, do not depend on external code
+
+`deno_std` is intended to be baseline functionality that all Deno programs can
+rely on. We want to guarantee to users that this code does not include
+potentially unreviewed third party code.
+
+### Within `deno_std`, minimize dependencies; do not make circular imports.
+
+Although `deno_std` is a standalone codebase, we must still be careful to keep
+the internal dependencies simple and manageable. In particular, be careful to
+not to introduce circular imports.
+
+### For consistency, use underscores, not dashes in filenames.
+
+Example: Instead of `file-server.ts` use `file_server.ts`.
+
+### Format code according using prettier.
+
+More specifically, code should be wrapped at 80 columns and use 2-space
+indentation and use camel-case. Use `//format.ts` to invoke prettier.
+
+### Use JS Doc to document exported machinery
+
+We strive for complete documentation. Every exported symbol ideally should have
+a documentation line.
+
+If possible, use a single line for the JS Doc. Example:
+
+```ts
+/** foo does bar. */
+export function foo() {
+  // ...
+}
+```
+
+See [CONTRIBUTING.md](https://github.com/denoland/deno/blob/master/.github/CONTRIBUTING.md#documenting-apis)
+for more details.
+
+### TODO Comments
+
+TODO comments should be include an issue or the author's github username in
+parentheses. Example:
+
+```
+// TODO(ry) Add tests.
+// TODO(#123) Support Windows.
+```
+
+### Copyright headers
+
+Most files in `deno_std` should have the following copyright header:
+
+```
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+```
+
+If the code originates elsewhere, ensure that the file has the proper copyright
+headers. We only allows MIT, BSD, and Apache licensed code in `deno_std`.
+
+### Top level functions should not use arrow syntax
+
+Top level functions should use the `function` keyword. Arrow syntax should be
+limited to closures.
+
+Bad
+
+```
+export const foo(): string => {
+  return "bar";
+}
+```
+
+Good
+
+```
+export function foo(): string {
+  return "bar";
+}
+```
+
+### When referencing Deno online, use the #denoland tag.
+
+The name "deno" unfortunately is not especially unique on the internet. In order
+to centralize the community, please tag github project, tweet, and other content
+with `#denoland`.
+
 ---
 
 Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
diff --git a/colors/README.md b/colors/README.md
index 72845b092..eafdbb9c1 100644
--- a/colors/README.md
+++ b/colors/README.md
@@ -1,7 +1,7 @@
 # colors
 
-Is a basic console color library intended for [Deno](https://deno.land/). It is
-inspired by packages like [chalk](https://www.npmjs.com/package/chalk) and
+Is a basic console color module intended for [Deno](https://deno.land/). It is
+inspired by [chalk](https://www.npmjs.com/package/chalk) and
 [colors](https://www.npmjs.com/package/colors) on npm.
 
 ## Usage