add es module file and declaration

This adds a main file for es modules. Is is generated in the same way as
the ts types from the list of names.

CONTRIBUTING.md

@@ -8,4 +8,5 @@ When adding a type class to __README.md__, please update __names__ then run:
 ```console
 $ npm run generate-js
 $ npm run generate-ts
+$ npm run generate-es
 ```

index.mjs

@@ -0,0 +1,22 @@
+export const equals = 'fantasy-land/equals';
+export const lte = 'fantasy-land/lte';
+export const compose = 'fantasy-land/compose';
+export const id = 'fantasy-land/id';
+export const concat = 'fantasy-land/concat';
+export const empty = 'fantasy-land/empty';
+export const invert = 'fantasy-land/invert';
+export const filter = 'fantasy-land/filter';
+export const map = 'fantasy-land/map';
+export const contramap = 'fantasy-land/contramap';
+export const ap = 'fantasy-land/ap';
+export const of = 'fantasy-land/of';
+export const alt = 'fantasy-land/alt';
+export const zero = 'fantasy-land/zero';
+export const reduce = 'fantasy-land/reduce';
+export const traverse = 'fantasy-land/traverse';
+export const chain = 'fantasy-land/chain';
+export const chainRec = 'fantasy-land/chainRec';
+export const extend = 'fantasy-land/extend';
+export const extract = 'fantasy-land/extract';
+export const bimap = 'fantasy-land/bimap';
+export const promap = 'fantasy-land/promap';

package.json

@@ -31,12 +31,15 @@
     "/README.md",
     "/index.d.ts",
     "/index.js",
+    "/index.mjs",
     "/package.json"
   ],
   "main": "index.js",
   "types": "index.d.ts",
+  "module": "index.mjs",
   "scripts": {
     "doctest": "sanctuary-doctest",
+    "generate-es": "scripts/generate-es",
     "generate-js": "scripts/generate-js",
     "generate-ts": "scripts/generate-ts",
     "lint": "sanctuary-lint",

scripts/generate-es

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+set -euf -o pipefail
+
+awk '{ print "export const " $0 " = \047fantasy-land/" $0 "\047;" }' names >index.mjs

scripts/lint

@@ -5,3 +5,4 @@ node_modules/.bin/sanctuary-lint "$@"
 
 scripts/generate-js && git diff --exit-code index.js
 scripts/generate-ts && git diff --exit-code index.d.ts
+scripts/generate-es && git diff --exit-code index.mjs