refactor cmd to command, document, and make netlify.toml dev block overrides explicit

src/detect-server.js

@@ -1,20 +1,8 @@
-const gatsbyDetector = require('./detectors/gatsby')
-const reactStaticDetector = require('./detectors/react-static')
-const craDetector = require('./detectors/cra')
-const hugoDetector = require('./detectors/hugo')
-const eleventyDetector = require('./detectors/eleventy')
-const jekyllDetector = require('./detectors/jekyll')
-const vueDetector = require('./detectors/vue')
-
-const detectors = [
-  gatsbyDetector,
-  reactStaticDetector,
-  hugoDetector,
-  jekyllDetector,
-  eleventyDetector,
-  craDetector,
-  vueDetector
-]
+const path = require('path')
+const detectors = require('fs')
+  .readdirSync(path.join(__dirname, 'detectors'))
+  .filter(x => x.endsWith('.js')) // only accept .js detector files
+  .map(det => require(path.join(__dirname, `detectors/${det}`)))
 
 module.exports.serverSettings = devConfig => {
   let settings = null
@@ -27,16 +15,28 @@ module.exports.serverSettings = devConfig => {
 
   if (devConfig) {
     settings = settings || {}
-    if (devConfig.cmd) {
-      settings.cmd = devConfig.cmd.split(/\s/)[0]
-      settings.args = devConfig.cmd.split(/\s/).slice(1)
+    if (devConfig.command) {
+      settings.command = devConfig.command.split(/\s/)[0]
+      assignLoudly(devConfig, 'command', settings, 'command')
+      settings.args = devConfig.command.split(/\s/).slice(1)
+      assignLoudly(devConfig, 'args', settings, 'args')
     }
     if (devConfig.port) {
-      settings.proxyPort = devConfig.port
+      assignLoudly(devConfig, 'port', settings, 'proxyPort')
       settings.urlRegexp = devConfig.urlRegexp || new RegExp(`(http://)([^:]+:)${devConfig.port}(/)?`, 'g')
     }
-    settings.dist = devConfig.publish || settings.dist
+    assignLoudly(devConfig, 'publish', settings, 'dist')
   }
 
   return settings
 }
+
+// does assignAndTellUserIfNetlifyTomlDevBlockOverride
+// mutates the settings field
+function assignLoudly(devConfig, field, settings, settingsField) {
+  if (settings[settingsField] !== devConfig[field]) {
+    // silent if command is exactly same
+    console.log(`Using ${field} from netlify.toml [dev] block: `, devConfig[field])
+    settings[settingsField] === devConfig[field]
+  }
+}

src/detectors/README.md

@@ -0,0 +1,23 @@
+## writing a detector
+
+- write as many checks as possible to fit your project
+- return false if its not your project
+- if it definitely is, return an object with this shape:
+
+```ts
+{
+    cmd: String, // e.g. yarn, npm
+    port: Number, // e.g. 8888
+    proxyPort: Number, // e.g. 3000
+    env: Object, // env variables, see examples
+    args: String, // e.g 'run develop', so that the combined command is 'npm run develop'
+    urlRegexp: RegExp, // see examples
+    dist: String // e.g. 'dist' or 'build'
+}
+```
+
+## things to note
+
+- Dev block overrides will supercede anything you write in your detector: https://github.com/netlify/netlify-dev-plugin#project-detection
+- detectors are language agnostic. don't assume npm or yarn.
+- if default args (like 'develop') are missing, that means the user has configured it, best to tell them to use the -c flag.

src/detectors/cra.js

@@ -20,7 +20,7 @@ module.exports = function() {
 
   const yarnExists = existsSync('yarn.lock')
   return {
-    cmd: yarnExists ? 'yarn' : 'npm',
+    command: yarnExists ? 'yarn' : 'npm',
     port: 8888,
     proxyPort: 3000,
     env: { ...process.env, BROWSER: 'none', PORT: 3000 },

src/detectors/eleventy.js

@@ -9,7 +9,7 @@ module.exports = function() {
     port: 8888,
     proxyPort: 8080,
     env: { ...process.env },
-    cmd: 'npx',
+    command: 'npx',
     args: ['eleventy', '--serve', '--watch'],
     urlRegexp: new RegExp(`(http://)([^:]+:)${8080}(/)?`, 'g'),
     dist: '_site'

src/detectors/gatsby.js

@@ -7,7 +7,7 @@ module.exports = function() {
 
   const yarnExists = existsSync('yarn.lock')
   return {
-    cmd: yarnExists ? 'yarn' : 'npm',
+    command: yarnExists ? 'yarn' : 'npm',
     port: 8888,
     proxyPort: 8000,
     env: { ...process.env },

src/detectors/hugo.js

@@ -9,7 +9,7 @@ module.exports = function() {
     port: 8888,
     proxyPort: 1313,
     env: { ...process.env },
-    cmd: 'hugo',
+    command: 'hugo',
     args: ['server', '-w'],
     urlRegexp: new RegExp(`(http://)([^:]+:)${1313}(/)?`, 'g'),
     dist: 'public'

src/detectors/jekyll.js

@@ -9,7 +9,7 @@ module.exports = function() {
     port: 8888,
     proxyPort: 4000,
     env: { ...process.env },
-    cmd: 'bundle',
+    command: 'bundle',
     args: ['exec', 'jekyll', 'serve', '-w', '-l'],
     urlRegexp: new RegExp(`(http://)([^:]+:)${4000}(/)?`, 'g'),
     dist: '_site'

src/detectors/react-static.js

@@ -7,7 +7,7 @@ module.exports = function() {
 
   const yarnExists = existsSync('yarn.lock')
   return {
-    cmd: yarnExists ? 'yarn' : 'npm',
+    command: yarnExists ? 'yarn' : 'npm',
     port: 8888,
     proxyPort: 3000,
     env: { ...process.env },

src/detectors/vue.js

@@ -20,7 +20,7 @@ module.exports = function() {
 
   const yarnExists = existsSync('yarn.lock')
   return {
-    cmd: yarnExists ? 'yarn' : 'npm',
+    command: yarnExists ? 'yarn' : 'npm',
     port: 8888,
     proxyPort: 8080,
     env: { ...process.env },