feat: add default value handling and PWD resolution

README.md

@@ -42,6 +42,7 @@ of setting it properly.
 
 - [Installation](#installation)
 - [Usage](#usage)
+- [Default Values](#default-values)
 - [`cross-env` vs `cross-env-shell`](#cross-env-vs-cross-env-shell)
 - [Windows Issues](#windows-issues)
 - [Inspiration](#inspiration)
@@ -126,6 +127,43 @@ Pay special attention to the **triple backslash** `(\\\)` **before** the
 **double quotes** `(")` and the **absence** of **single quotes** `(')`. Both of
 these conditions have to be met in order to work both on Windows and UNIX.
 
+Note: `${PWD}` and `$PWD` substitute for the current working directory.
+
+## Default Values
+
+To reference an environment variable and provide a default value if that
+variable is empty or not-defined, use the syntax:
+
+```bash
+${ENV_VAR_NAME:-default value}
+```
+
+Also supports recursive replacement in the default value allowing you to test
+multiple environment variables before showing a default
+
+```bash
+# Value of FIRST_VAR_TO_TEST or SECOND_VAR_TO_TEST environment variable if blank or undefined.
+# If both are blank or undefined, replace with an empty string
+${FIRST_VAR_TO_TEST:-$SECOND_VAR_TO_TEST}
+```
+
+Can nest as many as you want
+
+```bash
+# Value of FIRST_VAR_TO_TEST, then SECOND_VAR_TO_TEST then THIRD_VAR_TO_TEST environment variables.
+# If all are blank or undefined, the string "default value if all are empty or undefined"
+${FIRST_VAR_TO_TEST:-${SECOND_VAR_TO_TEST:-${THIRD_VAR_TO_TEST:-default value if all are empty or undefined}}}
+```
+
+Or even use multiple environment variables in the default values
+
+```bash
+${NODE_DEBUG_OPTIONS:---inspect=$NODE_DEBUG_PORT $NODE_DEFAULT_OPTIONS}
+```
+
+This follows the UNIX standard for environment variables and works for both
+`cross-env` and `cross-env-shell`.
+
 ## `cross-env` vs `cross-env-shell`
 
 The `cross-env` module exposes two bins: `cross-env` and `cross-env-shell`. The
@@ -173,8 +211,6 @@ easier for Windows users.
 
 - [`env-cmd`](https://github.com/toddbluhm/env-cmd) - Reads environment
   variables from a file instead
-- [`@naholyr/cross-env`](https://www.npmjs.com/package/@naholyr/cross-env) -
-  `cross-env` with support for setting default values
 
 ## Contributors
 
@@ -208,6 +244,7 @@ Thanks goes to these people ([emoji key][emojis]):
     <td align="center"><a href="https://nz.linkedin.com/in/jsonc11"><img src="https://avatars0.githubusercontent.com/u/5185660?v=4" width="100px;" alt="Jason Cooke"/><br /><sub><b>Jason Cooke</b></sub></a><br /><a href="https://github.com/kentcdodds/cross-env/commits?author=Jason-Cooke" title="Documentation">📖</a></td>
     <td align="center"><a href="https://github.com/bibo5088"><img src="https://avatars0.githubusercontent.com/u/17709887?v=4" width="100px;" alt="bibo5088"/><br /><sub><b>bibo5088</b></sub></a><br /><a href="https://github.com/kentcdodds/cross-env/commits?author=bibo5088" title="Code">💻</a></td>
     <td align="center"><a href="https://codefund.io"><img src="https://avatars2.githubusercontent.com/u/12481?v=4" width="100px;" alt="Eric Berry"/><br /><sub><b>Eric Berry</b></sub></a><br /><a href="#fundingFinding-coderberry" title="Funding Finding">🔍</a></td>
+    <td align="center"><a href="https://github.com/yinzara"><img src="https://avatars2.githubusercontent.com/u/671855?v=4" width="100px;" alt="Matt Morrissette"/><br /><sub><b>Matt Morrissette</b></sub></a><br /><a href="https://github.com/kentcdodds/cross-env/commits?author=yinzara" title="Code">💻</a><a href="https://github.com/kentcdodds/cross-env/commits?author=yinzara" title="Documentation">📖</a><a href="https://github.com/kentcdodds/cross-env/commits?author=yinzara" title="Tests">⚠️</a></td> 
   </tr>
 </table>
 

src/__tests__/command.js

@@ -1,3 +1,4 @@
+/* eslint-disable no-template-curly-in-string */
 const isWindowsMock = require('../is-windows')
 const commandConvert = require('../command')
 
@@ -59,7 +60,7 @@ test(`leaves embedded variables unchanged when using correct operating system`,
 
 test(`converts braced unix-style env variable usage for windows`, () => {
   isWindowsMock.mockReturnValue(true)
-  // eslint-disable-next-line no-template-curly-in-string
+
   expect(commandConvert('${test}', env)).toBe('%test%')
 })
 
@@ -79,3 +80,53 @@ test(`normalizes command on windows`, () => {
   // as `true` for command only
   expect(commandConvert('./cmd.bat', env, true)).toBe('cmd.bat')
 })
+
+test(`evaluates default values for missing environment variables on windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(commandConvert('$test1/${foo:-bar}/$test2', env)).toBe(
+    '%test1%/bar/%test2%',
+  )
+})
+
+test(`evaluates default values for empty environment variables on windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(commandConvert('$test1/${empty_var:-bang}/$test2', env)).toBe(
+    '%test1%/bang/%test2%',
+  )
+})
+
+test(`evaluates default values recursively for empty environment variables on windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(
+    commandConvert('$test1/${empty_var:-${missing_var:-bang}}/$test2', env),
+  ).toBe('%test1%/bang/%test2%')
+})
+
+test(`evaluates secondary values recursively for environment variables on windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(
+    commandConvert('$test1/${empty_var:-${test3:-bang}}/$test2', env),
+  ).toBe('%test1%/%test3%/%test2%')
+})
+
+test('resolves the current working directory inside string in windows', () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(commandConvert('cd ${PWD}\\ADirectory')).toBe(
+    `cd ${process.cwd()}\\ADirectory`,
+  )
+})
+
+test('resolves the current working directory inside string in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(commandConvert('cd ${PWD}/adir')).toBe('cd ${PWD}/adir')
+})
+
+test('All the escapes are belong to us in Windows', () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(
+    commandConvert(
+      'start-\\${ESCAPED:-a-\\}-val}-\\$ESCAPED-\\\\${ESCAPED:-a-\\}-val}-\\\\$test1-end',
+      env,
+    ),
+  ).toBe('start-${ESCAPED:-a-\\}-val}-$ESCAPED-\\a-}-val-\\%test1%-end')
+})

src/__tests__/variable.js

@@ -1,3 +1,4 @@
+/* eslint-disable no-template-curly-in-string */
 const isWindowsMock = require('../is-windows')
 const varValueConvert = require('../variable')
 
@@ -8,6 +9,7 @@ const JSON_VALUE = '{\\"foo\\":\\"bar\\"}'
 beforeEach(() => {
   process.env.VAR1 = 'value1'
   process.env.VAR2 = 'value2'
+  process.env.EMPTY_VAR = ''
   process.env.JSON_VAR = JSON_VALUE
 })
 
@@ -76,7 +78,6 @@ test(`resolves an env variable value`, () => {
 
 test(`resolves an env variable value with curly syntax`, () => {
   isWindowsMock.mockReturnValue(true)
-  // eslint-disable-next-line no-template-curly-in-string
   expect(varValueConvert('foo-${VAR1}')).toBe('foo-value1')
 })
 
@@ -105,6 +106,26 @@ test(`does not resolve an env variable prefixed with \\ on Windows`, () => {
   expect(varValueConvert('\\$VAR1')).toBe('$VAR1')
 })
 
+test(`does not resolve a $ without a word after it in UNIX`, () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('hello $ the case')).toBe('hello $ the case')
+})
+
+test(`does not resolve a $ without a word after it in Windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(varValueConvert('hello $ the case')).toBe('hello $ the case')
+})
+
+test(`does not resolve an env variable if it isn't prefix with a $ but is in curly braces \\ on UNIX`, () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('{VAR1}')).toBe('{VAR1}')
+})
+
+test(`does not resolve an env variable if it isn't prefix with a $ but is in curly braces \\ on Windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(varValueConvert('{VAR1}')).toBe('{VAR1}')
+})
+
 test(`does not resolve an env variable prefixed with \\ on UNIX`, () => {
   isWindowsMock.mockReturnValue(false)
   expect(varValueConvert('\\$VAR1')).toBe('$VAR1')
@@ -119,3 +140,134 @@ test(`resolves an env variable prefixed with \\\\ on UNIX`, () => {
   isWindowsMock.mockReturnValue(false)
   expect(varValueConvert('\\\\$VAR1')).toBe('\\value1')
 })
+
+test(`does not resolve an env variable prefixed with \\$\{ on Windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(varValueConvert('\\${VAR1}')).toBe('${VAR1}')
+})
+
+test(`does not resolve an env variable prefixed with on UNIX`, () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('\\${VAR1}')).toBe('${VAR1}')
+})
+
+test(`resolves an env variable prefixed with \\\\$\{ on Windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(varValueConvert('\\\\${VAR1}')).toBe('\\value1')
+})
+
+test(`resolves an env variable prefixed with \\\\$\{ on UNIX`, () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('\\\\${VAR1}')).toBe('\\value1')
+})
+
+test(`resolves default value for missing variable on UNIX`, () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('${UNKNOWN_UNIX_VAR:-defaultUnix}')).toBe(
+    'defaultUnix',
+  )
+})
+
+test(`resolves default value for missing variable on windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(varValueConvert('${UNKNOWN_WINDOWS_VAR:-defaultWindows}')).toBe(
+    'defaultWindows',
+  )
+})
+
+test(`resolves default value for empty string variable on UNIX`, () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('${EMPTY_VAR:-defaultUnix}')).toBe('defaultUnix')
+})
+
+test(`resolves default value for empty string variable on windows`, () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(varValueConvert('${EMPTY_VAR:-defaultWindows}')).toBe('defaultWindows')
+})
+
+test('resolves default value recursively when primary and secondary doesnt exist in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(
+    varValueConvert('${EMPTY_VAR:-foobar${MISSING_VAR:-defaultUnix}}'),
+  ).toBe('foobardefaultUnix')
+})
+
+test('resolves secondary value recursively when primary doesnt exist in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('${EMPTY_VAR:-bang${VAR1:-defaultUnix}}')).toBe(
+    'bangvalue1',
+  )
+})
+
+test('resolves default value recursively when primary and secondary doesnt exist in windows', () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(
+    varValueConvert('${EMPTY_VAR:-foobar${MISSING_VAR:-defaultWindows}}'),
+  ).toBe('foobardefaultWindows')
+})
+
+test('resolves secondary value recursively when primary doesnt exist in windows', () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(varValueConvert('${EMPTY_VAR:-bang${VAR1:-defaultWindows}}')).toBe(
+    'bangvalue1',
+  )
+})
+
+test('resolves the current working directory inside string in windows', () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(varValueConvert('${PWD}\\ADirectory')).toBe(
+    `${process.cwd()}\\ADirectory`,
+  )
+})
+
+test('resolves the current working directory inside string in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('${PWD}/adir')).toBe(`${process.cwd()}/adir`)
+})
+
+test('resolves a very complex string with defaults and PWD in Windows', () => {
+  isWindowsMock.mockReturnValue(true)
+  expect(
+    varValueConvert(
+      'start-${PWD}-${EMPTY_VAR:-${NO_VAR1:-$VAR1}}-${NO_VAR2:-$VAR2}-${NO_VAR3:-${EMPTY_VAR:-value3}}-${EMPTY_VAR:-$PWD}-end',
+    ),
+  ).toBe(`start-${process.cwd()}-value1-value2-value3-${process.cwd()}-end`)
+})
+
+test('sequential variables  resolves in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('start-$VAR1$VAR2-end')).toBe('start-value1value2-end')
+})
+
+test('sequential variables with brackets resolves in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('start-${VAR1}$VAR2-end')).toBe(
+    'start-value1value2-end',
+  )
+})
+
+test('sequential variables resolves in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('start-$VAR1$VAR2-end')).toBe('start-value1value2-end')
+})
+
+test('reversed sequential variables with brackets resolves in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('start-$VAR1${VAR2}-end')).toBe(
+    'start-value1value2-end',
+  )
+})
+
+test('escape closed curly brace in default value in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(varValueConvert('${EMPTY_VAR:-${UNKNOWN:-ba\\}r}}')).toBe('ba}r')
+})
+
+test('All the escapes are belong to us in UNIX', () => {
+  isWindowsMock.mockReturnValue(false)
+  expect(
+    varValueConvert(
+      'start-\\${ESCAPED:-a-\\}-val}-\\$ESCAPED-\\\\${ESCAPED:-a-\\}-val}-\\\\$VAR1-end',
+    ),
+  ).toBe('start-${ESCAPED:-a-\\}-val}-$ESCAPED-\\a-}-val-\\value1-end')
+})

src/command.js

@@ -1,5 +1,6 @@
 const path = require('path')
 const isWindows = require('./is-windows')
+const envReplace = require('./env-replace')
 
 module.exports = commandConvert
 
@@ -15,15 +16,7 @@ function commandConvert(command, env, normalize = false) {
   if (!isWindows()) {
     return command
   }
-  const envUnixRegex = /\$(\w+)|\${(\w+)}/g // $my_var or ${my_var}
-  const convertedCmd = command.replace(envUnixRegex, (match, $1, $2) => {
-    const varName = $1 || $2
-    // In Windows, non-existent variables are not replaced by the shell,
-    // so for example "echo %FOO%" will literally print the string "%FOO%", as
-    // opposed to printing an empty string in UNIX. See kentcdodds/cross-env#145
-    // If the env variable isn't defined at runtime, just strip it from the command entirely
-    return env[varName] ? `%${varName}%` : ''
-  })
+  const convertedCmd = envReplace(command, env, true)
   // Normalization is required for commands with relative paths
   // For example, `./cmd.bat`. See kentcdodds/cross-env#127
   // However, it should not be done for command arguments.