Build global flow typings (#558)

Possible solution for #534 (comment) in #534

CHANGELOG.md

@@ -81,6 +81,9 @@ for the list of changes made since `v2.0.0-alpha.1`.
 - [Vietnamese locale (vi)](https://github.com/date-fns/date-fns/pull/546)
   (kudos to [@trongthanh](https://github.com/trongthanh))
 
+- Flow typings for `index.js`, `fp/index.js`, `locale/index.js`, and their ESM equivalents.
+  See PR [#558](https://github.com/date-fns/date-fns/pull/558)
+
 ### Changed
 
 - **BREAKING**: function submodules now use camelCase naming schema:

scripts/_lib/listFPFns.js

@@ -3,7 +3,7 @@ const fs = require('fs')
 
 module.exports = listFPFns
 
-const ignoredFiles = ['index.js', 'test.js']
+const ignoredFiles = ['index.js', 'test.js', 'index.js.flow']
 
 function listFPFns () {
   const files = fs.readdirSync(path.join(process.cwd(), 'src', 'fp'))

scripts/_lib/listFns.js

@@ -3,7 +3,7 @@ const fs = require('fs')
 
 module.exports = listFns
 
-const ignoredFiles = ['locale', 'esm', 'fp', 'index.js', 'test.js']
+const ignoredFiles = ['locale', 'esm', 'fp', 'index.js', 'test.js', 'index.js.flow']
 
 function listFns () {
   const files = fs.readdirSync(path.join(process.cwd(), 'src'))

scripts/_lib/listLocales.js

@@ -1,7 +1,7 @@
 const path = require('path')
 const fs = require('fs')
 
-const ignoredFiles = ['index.js', 'test.js']
+const ignoredFiles = ['index.js', 'test.js', 'index.js.flow']
 
 module.exports = listLocales
 

scripts/build/package.sh

@@ -38,6 +38,9 @@ do
   cp -r "./src/$fnDir" "$dir/esm/"
 done
 
+# Copy global flow typing
+cp ./src/index.js.flow "$dir/esm/index.js.flow"
+
 # Copy esm indices
 cp ./src/esm/index.js "$dir/esm/index.js"
 cp ./src/esm/fp/index.js "$dir/esm/fp/index.js"

scripts/build/typings.js

@@ -381,6 +381,28 @@ function generateFlowFnTyping (fn, aliasDeclarations) {
   fs.writeFileSync(filename, typingString)
 }
 
+function generateFlowFnIndexTyping (fns, aliasDeclarations) {
+  const filename = `./src/index.js.flow`
+
+  const fnsDeclarations = fns.map(({title, args, content}) => {
+    const params = getParams(args, {indent: 1, leftBorder: '(', rightBorder: ')'})
+    const returns = getType(content.returns[0].type.names)
+    return `  ${title}: ${params} => ${returns}`
+  })
+
+  const typingString = ['// @flow']
+    .concat(generatedAutomaticallyMessage)
+    .concat('')
+    .concat(aliasDeclarations.join('\n\n'))
+    .concat('')
+    .concat(`declare module.exports: {`)
+    .concat(fnsDeclarations.join(',\n\n'))
+    .concat(`}\n`)
+    .join('\n')
+
+  fs.writeFileSync(filename, typingString)
+}
+
 function generateFlowFPFnTyping (fn, aliasDeclarations) {
   const {title, args, content} = fn
   const filename = `./src/fp/${title}/index.js.flow`
@@ -400,6 +422,28 @@ function generateFlowFPFnTyping (fn, aliasDeclarations) {
   fs.writeFileSync(filename, typingString)
 }
 
+function generateFlowFPFnIndexTyping (fns, aliasDeclarations) {
+  const filename = `./src/fp/index.js.flow`
+
+  const fnsDeclarations = fns.map(({title, args, content}) =>
+    `  ${title}: ${getFPFnType(args, content.returns[0].type.names)}`
+  )
+
+  const typingString = ['// @flow']
+    .concat(generatedAutomaticallyMessage)
+    .concat('')
+    .concat(aliasDeclarations.join('\n\n'))
+    .concat('')
+    .concat(flowFPAliases)
+    .concat('')
+    .concat(`declare module.exports: {`)
+    .concat(fnsDeclarations.join(',\n'))
+    .concat(`}\n`)
+    .join('\n')
+
+  fs.writeFileSync(filename, typingString)
+}
+
 function generateFlowLocaleTyping (locale, localeAliasDeclaration) {
   const {fullPath} = locale
   const filename = `${fullPath}.flow`
@@ -415,6 +459,22 @@ function generateFlowLocaleTyping (locale, localeAliasDeclaration) {
   fs.writeFileSync(filename, typingString)
 }
 
+function generateFlowLocaleIndexTyping (locales, localeAliasDeclaration) {
+  const filename = './src/locale/index.js.flow'
+
+  const typingString = ['// @flow']
+    .concat(generatedAutomaticallyMessage)
+    .concat('')
+    .concat(localeAliasDeclaration)
+    .concat('')
+    .concat(`declare module.exports: {`)
+    .concat(locales.map(({name}) => `  ${name}: Locale`).join(',\n'))
+    .concat(`}\n`)
+    .join('\n')
+
+  fs.writeFileSync(filename, typingString)
+}
+
 function generateFlowTypings (fns, aliases, locales) {
   const aliasDeclarations = aliases.map(getFlowTypeAlias)
   const localeAliasDeclaration = getFlowTypeAlias(aliases.find((alias) => alias.title === 'Locale'))
@@ -430,4 +490,8 @@ function generateFlowTypings (fns, aliases, locales) {
   locales.forEach((locale) => {
     generateFlowLocaleTyping(locale, localeAliasDeclaration)
   })
+
+  generateFlowFnIndexTyping(fns.filter(({isFPFn}) => !isFPFn), aliasDeclarations)
+  generateFlowFPFnIndexTyping(fns.filter(({isFPFn}) => isFPFn), aliasDeclarations)
+  generateFlowLocaleIndexTyping(locales, localeAliasDeclaration)
 }