feat: add npm set-script

Introduces the set-script command. It accepts two arguments,
the script name and the command

ref: https://github.com/npm/rfcs/blob/latest/accepted/0016-set-script-command.md

PR-URL: #2237
Credit: @Yash-Singh1
Close: #2237
Reviewed-by: @ruyadorno

docs/content/commands/npm-set-script.md

@@ -0,0 +1,34 @@
+---
+title: npm-set-script
+section: 1
+description: Set tasks in the scripts section of package.json
+---
+
+### Synopsis
+An npm command that lets you create a task in the scripts section of the package.json.
+
+```bash
+npm set-script [<script>] [<command>]
+```
+
+
+**Example:**
+
+* `npm set-script start "http-server ."`
+
+```json
+{
+  "name": "my-project",
+  "scripts": {
+    "start": "http-server .",
+    "test": "some existing value"
+  }
+}
+```
+
+### See Also
+
+* [npm run-script](/commands/npm-run-script)
+* [npm install](/commands/npm-install)
+* [npm test](/commands/npm-test)
+* [npm start](/commands/npm-start)

lib/set-script.js

@@ -0,0 +1,55 @@
+'use strict'
+
+const log = require('npmlog')
+const usageUtil = require('./utils/usage.js')
+const { localPrefix } = require('./npm.js')
+const fs = require('fs')
+const usage = usageUtil('set-script', 'npm set-script [<script>] [<command>]')
+const completion = require('./utils/completion/none.js')
+const parseJSON = require('json-parse-even-better-errors')
+const rpj = require('read-package-json-fast')
+
+const cmd = (args, cb) => set(args).then(() => cb()).catch(cb)
+
+const set = async function (args) {
+  if (process.env.npm_lifecycle_event === 'postinstall')
+    throw new Error('Scripts can’t set from the postinstall script')
+
+  // Parse arguments
+  if (args.length !== 2)
+    throw new Error(`Expected 2 arguments: got ${args.length}`)
+
+  // Set the script
+  let manifest
+  let warn = false
+  try {
+    manifest = fs.readFileSync(localPrefix + '/package.json', 'utf-8')
+  } catch (error) {
+    throw new Error('package.json not found')
+  }
+  try {
+    manifest = parseJSON(manifest)
+  } catch (error) {
+    throw new Error(`Invalid package.json: ${error}`)
+  }
+  if (!manifest.scripts)
+    manifest.scripts = {}
+  if (manifest.scripts[args[0]] && manifest.scripts[args[0]] !== args[1])
+    warn = true
+  manifest.scripts[args[0]] = args[1]
+  // format content
+  const packageJsonInfo = await rpj(localPrefix + '/package.json')
+  const {
+    [Symbol.for('indent')]: indent,
+    [Symbol.for('newline')]: newline,
+  } = packageJsonInfo
+  const format = indent === undefined ? '  ' : indent
+  const eol = newline === undefined ? '\n' : newline
+  const content = (JSON.stringify(manifest, null, format) + '\n')
+    .replace(/\n/g, eol)
+  fs.writeFileSync(localPrefix + '/package.json', content)
+  if (warn)
+    log.warn('set-script', `Script "${args[0]}" was overwritten`)
+}
+
+module.exports = Object.assign(cmd, { usage, completion })

lib/utils/cmd-list.js

@@ -127,6 +127,7 @@ const cmdList = [
   'start',
   'restart',
   'run-script',
+  'set-script',
   'completion',
   'doctor',
   'exec',

tap-snapshots/test-lib-utils-cmd-list.js-TAP.test.js

@@ -162,6 +162,7 @@ Object {
     "start",
     "restart",
     "run-script",
+    "set-script",
     "completion",
     "doctor",
     "exec",

test/coverage-map.js

@@ -9,9 +9,8 @@ const coverageMap = (filename) => {
     return glob.sync(`${dir}/**/*.js`)
       .map(f => relative(process.cwd(), f))
   }
-  if (/^test\/(lib|bin)\//.test(filename)) {
+  if (/^test\/(lib|bin)\//.test(filename))
     return filename.replace(/^test\//, '')
-  }
   return []
 }
 

test/lib/set-script.js

@@ -0,0 +1,154 @@
+const test = require('tap')
+const requireInject = require('require-inject')
+const setScriptDefault = require('../../lib/set-script.js')
+const parseJSON = require('json-parse-even-better-errors')
+
+test.type(setScriptDefault, 'function', 'command is function')
+test.equal(setScriptDefault.completion, require('../../lib/utils/completion/none.js'), 'empty completion')
+test.equal(setScriptDefault.usage, 'npm set-script [<script>] [<command>]', 'usage matches')
+test.test('fails on invalid arguments', (t) => {
+  const setScript = requireInject('../../lib/set-script.js', {
+    fs: {},
+    npmlog: {},
+  })
+  t.plan(3)
+  setScript(['arg1'], (fail) => t.match(fail, /Expected 2 arguments: got 1/))
+  setScript(['arg1', 'arg2', 'arg3'], (fail) => t.match(fail, /Expected 2 arguments: got 3/))
+  setScript(['arg1', 'arg2', 'arg3', 'arg4'], (fail) => t.match(fail, /Expected 2 arguments: got 4/))
+})
+test.test('fails if run in postinstall script', (t) => {
+  var originalVar = process.env.npm_lifecycle_event
+  process.env.npm_lifecycle_event = 'postinstall'
+  const setScript = requireInject('../../lib/set-script.js', {
+    fs: {},
+    npmlog: {},
+  })
+  t.plan(1)
+  setScript(['arg1', 'arg2'], (fail) => t.equal(fail.toString(), 'Error: Scripts can’t set from the postinstall script'))
+  process.env.npm_lifecycle_event = originalVar
+})
+test.test('fails when package.json not found', (t) => {
+  const setScript = requireInject('../../lib/set-script.js', {
+    '../../lib/npm.js': {
+      localPrefix: 'IDONTEXIST',
+    },
+  })
+  t.plan(1)
+  setScript(['arg1', 'arg2'], (fail) => t.match(fail, /package.json not found/))
+})
+test.test('fails on invalid JSON', (t) => {
+  const setScript = requireInject('../../lib/set-script.js', {
+    fs: {
+      readFileSync: (name, charcode) => {
+        return 'iamnotjson'
+      },
+    },
+  })
+  t.plan(1)
+  setScript(['arg1', 'arg2'], (fail) => t.match(fail, /Invalid package.json: JSONParseError/))
+})
+test.test('creates scripts object', (t) => {
+  var mockFile = ''
+  const setScript = requireInject('../../lib/set-script.js', {
+    fs: {
+      readFileSync: (name, charcode) => {
+        return '{}'
+      },
+      writeFileSync: (location, inner) => {
+        mockFile = inner
+      },
+    },
+    'read-package-json-fast': async function (filename) {
+      return {
+        [Symbol.for('indent')]: '  ',
+        [Symbol.for('newline')]: '\n',
+      }
+    },
+  })
+  t.plan(2)
+  setScript(['arg1', 'arg2'], (error) => {
+    t.equal(error, undefined)
+    t.assert(parseJSON(mockFile), {scripts: {arg1: 'arg2'}})
+  })
+})
+test.test('warns before overwriting', (t) => {
+  var warningListened = ''
+  const setScript = requireInject('../../lib/set-script.js', {
+    fs: {
+      readFileSync: (name, charcode) => {
+        return JSON.stringify({
+          scripts: {
+            arg1: 'blah',
+          },
+        })
+      },
+      writeFileSync: (name, content) => {},
+    },
+    'read-package-json-fast': async function (filename) {
+      return {
+        [Symbol.for('indent')]: '  ',
+        [Symbol.for('newline')]: '\n',
+      }
+    },
+    npmlog: {
+      warn: (prefix, message) => {
+        warningListened = message
+      },
+    },
+  })
+  t.plan(2)
+  setScript(['arg1', 'arg2'], (error) => {
+    t.equal(error, undefined, 'no error')
+    t.equal(warningListened, 'Script "arg1" was overwritten')
+  })
+})
+test.test('provided indentation and eol is used', (t) => {
+  var mockFile = ''
+  const setScript = requireInject('../../lib/set-script.js', {
+    fs: {
+      readFileSync: (name, charcode) => {
+        return '{}'
+      },
+      writeFileSync: (name, content) => {
+        mockFile = content
+      },
+    },
+    'read-package-json-fast': async function (filename) {
+      return {
+        [Symbol.for('indent')]: ' '.repeat(6),
+        [Symbol.for('newline')]: '\r\n',
+      }
+    },
+  })
+  t.plan(3)
+  setScript(['arg1', 'arg2'], (error) => {
+    t.equal(error, undefined)
+    t.equal(mockFile.split('\r\n').length > 1, true)
+    t.equal(mockFile.split('\r\n').every((value) => !value.startsWith(' ') || value.startsWith(' '.repeat(6))), true)
+  })
+})
+test.test('goes to default when undefined indent and eol provided', (t) => {
+  var mockFile = ''
+  const setScript = requireInject('../../lib/set-script.js', {
+    fs: {
+      readFileSync: (name, charcode) => {
+        return '{}'
+      },
+      writeFileSync: (name, content) => {
+        mockFile = content
+      },
+    },
+    'read-package-json-fast': async function (filename) {
+      return {
+        [Symbol.for('indent')]: undefined,
+        [Symbol.for('newline')]: undefined,
+      }
+    },
+  })
+  t.plan(3)
+  setScript(['arg1', 'arg2'], (error) => {
+    t.equal(error, undefined)
+    t.equal(mockFile.split('\n').length > 1, true)
+    t.equal(mockFile.split('\n').every((value) => !value.startsWith(' ') || value.startsWith('  ')), true)
+  })
+})