feat: add --before-write cli option (#89)

* feat: add `--before-write` cli option

* refactor: cleanup before write wrapper

* docs: add before-write docs

Author: chenasraf

docs/docs/usage/03-cli.md

@@ -11,24 +11,57 @@ Usage: simple-scaffold [options]
 To see this and more information anytime, add the `-h` or `--help` flag to your call, e.g.
 `npx simple-scaffold@latest -h`.
 
-| Command \| alias                    |                                                                                                                                                                                                         |
-| ----------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `--name` \| `-n`                    | Name to be passed to the generated files. `{{name}}` and other data parameters inside contents and file names will be replaced accordingly. You may omit the `--name` or `-n` for this specific option. |
-| `--config`\|`-c`                    | Filename or directory to load config from                                                                                                                                                               |
-| `--git`\|`-g`                       | Git URL or GitHub path to load a template from.                                                                                                                                                         |
-| `--key` \| `-k`                     | Key to load inside the config file. This overwrites the config key provided after the colon in `--config` (e.g. `--config scaffold.cmd.js:component`)                                                   |
-| `--output` \| `-o`                  | Path to output to. If `--create-sub-folder` is enabled, the subfolder will be created inside this path. Default is current working directory.                                                           |
-| `--templates` \| `-t`               | Template files to use as input. You may provide multiple files, each of which can be a relative or absolute path, or a glob pattern for multiple file matching easily.                                  |
-| `--overwrite` \| `-w`               | Enable to override output files, even if they already exist.                                                                                                                                            |
-| `--data` \| `-d`                    | Add custom data to the templates. By default, only your app name is included.                                                                                                                           |
-| `--append-data` \| `-D`             | Append additional custom data to the templates, which will overwrite `--data`, using an alternate syntax, which is easier to use with CLI: `-D key1=string -D key2:=raw`                                |
-| `--create-sub-folder` \| `-s`       | Create subfolder with the input name                                                                                                                                                                    |
-| `--sub-folder-name-helper` \| `-sh` | Default helper to apply to subfolder name when using `--create-sub-folder true`.                                                                                                                        |
-| `--quiet` \| `-q`                   | Suppress output logs (Same as `--log-level none`)                                                                                                                                                       |
-| `--log-level` \| `-l`               | Determine amount of logs to display. The values are: `none \| debug \| info \| warn \| error`. The provided level will display messages of the same level or higher.                                    |
-| `--dry-run` \| `-dr`                | Don't emit files. This is good for testing your scaffolds and making sure they don't fail, without having to write actual file contents or create directories.                                          |
-| `--help` \| `-h`                    | Show this help message                                                                                                                                                                                  |
-| `--version` \| `-v`                 | Display version.                                                                                                                                                                                        |
+| Command \| alias                    |                                                                                                                                                                                                          |
+| ----------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `--name` \| `-n`                    | Name to be passed to the generated files. `{{name}}` and other data parameters inside contents and file names will be replaced accordingly. You may omit the `--name` or `-n` for this specific option.  |
+| `--config`\|`-c`                    | Filename or directory to load config from                                                                                                                                                                |
+| `--git`\|`-g`                       | Git URL or GitHub path to load a template from.                                                                                                                                                          |
+| `--key` \| `-k`                     | Key to load inside the config file. This overwrites the config key provided after the colon in `--config` (e.g. `--config scaffold.cmd.js:component`)                                                    |
+| `--output` \| `-o`                  | Path to output to. If `--create-sub-folder` is enabled, the subfolder will be created inside this path. Default is current working directory.                                                            |
+| `--templates` \| `-t`               | Template files to use as input. You may provide multiple files, each of which can be a relative or absolute path, or a glob pattern for multiple file matching easily.                                   |
+| `--overwrite` \| `-w`               | Enable to override output files, even if they already exist.                                                                                                                                             |
+| `--data` \| `-d`                    | Add custom data to the templates. By default, only your app name is included.                                                                                                                            |
+| `--append-data` \| `-D`             | Append additional custom data to the templates, which will overwrite `--data`, using an alternate syntax, which is easier to use with CLI: `-D key1=string -D key2:=raw`                                 |
+| `--create-sub-folder` \| `-s`       | Create subfolder with the input name                                                                                                                                                                     |
+| `--sub-folder-name-helper` \| `-sh` | Default helper to apply to subfolder name when using `--create-sub-folder true`.                                                                                                                         |
+| `--quiet` \| `-q`                   | Suppress output logs (Same as `--log-level none`)                                                                                                                                                        |
+| `--log-level` \| `-l`               | Determine amount of logs to display. The values are: `none \| debug \| info \| warn \| error`. The provided level will display messages of the same level or higher.                                     |
+| `--before-write` \| `-B`            | Run a script before writing the files. This can be a command or a path to a file. A temporary file path will be passed to the given command and the command should return a string for the final output. |
+| `--dry-run` \| `-dr`                | Don't emit files. This is good for testing your scaffolds and making sure they don't fail, without having to write actual file contents or create directories.                                           |
+| `--help` \| `-h`                    | Show this help message                                                                                                                                                                                   |
+| `--version` \| `-v`                 | Display version.                                                                                                                                                                                         |
+
+### Before Write option
+
+This option allows you to preprocess a file before it is being written, such as running a formatter,
+linter or other commands.
+
+To use this option, pass it the command you would like to run. The following tokens will be replaced
+in your string:
+
+- `{{path}}` - the temporary file path for you to read from
+- `{{rawpath}}` - a different file path containing the raw file contents **before** they were
+  handled by Handlebars.js.
+
+If none of these tokens are found, the regular (non-raw) path will be appended to the end of the
+command.
+
+```shell
+simple-scaffold -c . --before-write prettier
+# command: prettier /tmp/somefile
+
+simple-scaffold -c . --before-write 'cat {{path}} | my-linter'
+# command: cat /tmp/somefile | my-linter
+```
+
+The command should return the string to write to the file through standard output (stdout), and not
+re-write the tmp file as it is not used for writing. Returning an empty string (after trimming) will
+discard the result and write the original file contents.
+
+See
+[beforeWrite](https://chenasraf.github.io/simple-scaffold/docs/api/interfaces/ScaffoldConfig#beforewrite)
+Node.js API for more details. Instead of returning `undefined` to keep the default behavior, you can
+output `''` for the same effect.
 
 ## Examples:
 

docs/docs/usage/04-node.md

@@ -2,6 +2,8 @@
 title: Node.js Usage
 ---
 
+## Overview
+
 You can build the scaffold yourself, if you want to create more complex arguments, scaffold groups,
 etc - simply pass a config object to the Scaffold function when you are ready to start.
 
@@ -33,6 +35,19 @@ interface ScaffoldConfig {
 }
 ```
 
+### Before Write option
+
+This option allows you to preprocess a file before it is being written, such as running a formatter,
+linter or other commands.
+
+To use this option, you can run any async/blocking command, and return a string as the final output
+to be used as the file contents.
+
+Returning `undefined` will keep the file contents as-is, after normal Handlebars.js procesing by
+Simple Scaffold.
+
+## Example
+
 This is an example of loading a complete scaffold via Node.js:
 
 ```typescript
@@ -50,6 +65,8 @@ const config = {
   helpers: {
     twice: (text) => [text, text].join(" ")
   },
+  // return a string to replace the final file contents after pre-processing, or `undefined`
+  // to keep it as-is
   beforeWrite: (content, rawContent, outputPath) => content.toString().toUpperCase()
 }
 

examples/test-input/Component/{{pascalCase name}}.tsx

@@ -1,7 +1,7 @@
 import * as React from "react"
-import * as css from "./{{pascalCae name}}.css"
+import * as css from "./{{pascalCase name}}.css"
 
-class {{pascalCae name}} extends React.Component<any> {
+class {{pascalCase name}} extends React.Component<any> {
   private {{ property }}
 
   constructor(props: any) {
@@ -10,8 +10,8 @@ class {{pascalCae name}} extends React.Component<any> {
   }
 
   public render() {
-    return <div className={ css.{{pascalCae name}} } />
+    return <div className={ css.{{pascalCase name}} } />
   }
 }
 
-export default {pascalCae nName}}
+export default {{pascalCase name}}

src/cmd.ts

@@ -1,15 +1,15 @@
 #!/usr/bin/env node
 
-import os from "node:os"
+import path from "node:path"
+import fs from "node:fs/promises"
 import { massarg } from "massarg"
 import chalk from "chalk"
 import { ListCommandCliOptions, LogLevel, ScaffoldCmdConfig } from "./types"
 import { Scaffold } from "./scaffold"
-import path from "node:path"
-import fs from "node:fs/promises"
 import { getConfigFile, parseAppendData, parseConfigFile } from "./config"
 import { log } from "./logger"
 import { MassargCommand } from "massarg/command"
+import { getUniqueTmpPath as generateUniqueTmpPath } from "./file"
 
 export async function parseCliArgs(args = process.argv.slice(2)) {
   const isProjectRoot = Boolean(await fs.stat(path.join(__dirname, "package.json")).catch(() => false))
@@ -30,7 +30,7 @@ export async function parseCliArgs(args = process.argv.slice(2)) {
         return
       }
       log(config, LogLevel.info, `Simple Scaffold v${pkg.version}`)
-      const tmpPath = path.resolve(os.tmpdir(), `scaffold-config-${Date.now()}`)
+      const tmpPath = generateUniqueTmpPath()
       try {
         log(config, LogLevel.debug, "Parsing config file...", config)
         const parsed = await parseConfigFile(config, tmpPath)
@@ -144,6 +144,14 @@ export async function parseCliArgs(args = process.argv.slice(2)) {
         return val
       },
     })
+    .option({
+      name: "before-write",
+      aliases: ["B"],
+      description:
+        "Run a script before writing the files. This can be a command or a path to a" +
+        " file. A temporary file path will be passed to the given command and the command should " +
+        "return a string for the final output.",
+    })
     .flag({
       name: "dry-run",
       aliases: ["dr"],
@@ -163,7 +171,7 @@ export async function parseCliArgs(args = process.argv.slice(2)) {
         aliases: ["ls"],
         description: "List all available templates for a given config. See `list -h` for more information.",
         run: async (_config) => {
-          const tmpPath = path.resolve(os.tmpdir(), `scaffold-config-${Date.now()}`)
+          const tmpPath = generateUniqueTmpPath()
           const config = {
             templates: [],
             name: "",

src/config.ts

@@ -16,7 +16,8 @@ import { handlebarsParse } from "./parser"
 import { log } from "./logger"
 import { resolve, wrapNoopResolver } from "./utils"
 import { getGitConfig } from "./git"
-import { isDir, pathExists } from "./file"
+import { createDirIfNotExists, getUniqueTmpPath, isDir, pathExists } from "./file"
+import { exec, spawn } from "node:child_process"
 
 /** @internal */
 export function getOptionValueForFile<T>(
@@ -80,7 +81,7 @@ export async function getConfigFile(config: ScaffoldCmdConfig, tmpPath: string):
 
 /** @internal */
 export async function parseConfigFile(config: ScaffoldCmdConfig, tmpPath: string): Promise<ScaffoldConfig> {
-  let output: ScaffoldConfig = config
+  let output: ScaffoldConfig = { ...config, beforeWrite: undefined }
 
   if (config.quiet) {
     config.logLevel = LogLevel.none
@@ -101,6 +102,7 @@ export async function parseConfigFile(config: ScaffoldCmdConfig, tmpPath: string
     output = {
       ...config,
       ...imported,
+      beforeWrite: undefined,
       data: {
         ...(imported as any).data,
         ...config.data,
@@ -109,9 +111,12 @@ export async function parseConfigFile(config: ScaffoldCmdConfig, tmpPath: string
   }
 
   output.data = { ...output.data, ...config.appendData }
+  output.beforeWrite = config.beforeWrite ? wrapBeforeWrite(config, config.beforeWrite) : undefined
+
   if (!output.name) {
     throw new Error("simple-scaffold: Missing required option: name")
   }
+
   log(output, LogLevel.debug, "Parsed config", output)
   return output
 }
@@ -182,3 +187,72 @@ export async function findConfigFile(root: string): Promise<string> {
   }
   throw new Error(`Could not find config file in git repo`)
 }
+
+function wrapBeforeWrite(
+  config: LogConfig & Pick<ScaffoldConfig, "dryRun">,
+  beforeWrite: string,
+): ScaffoldConfig["beforeWrite"] {
+  return async (content, rawContent, outputFile) => {
+    const tmpPath = path.join(getUniqueTmpPath(), path.basename(outputFile))
+    await createDirIfNotExists(path.dirname(tmpPath), config)
+    const ext = path.extname(outputFile)
+    const rawTmpPath = tmpPath.replace(ext, ".raw" + ext)
+    try {
+      log(config, LogLevel.debug, "Parsing beforeWrite command", beforeWrite)
+      let cmd = await prepareBeforeWriteCmd({ beforeWrite, tmpPath, content, rawTmpPath, rawContent })
+      const result = await new Promise<string | undefined>((resolve, reject) => {
+        log(config, LogLevel.debug, "Running parsed beforeWrite command:", cmd)
+        const proc = exec(cmd)
+        proc.stdout!.on("data", (data) => {
+          if (data.trim()) {
+            resolve(data.toString())
+          } else {
+            resolve(undefined)
+          }
+        })
+        proc.stderr!.on("data", (data) => {
+          reject(data.toString())
+        })
+      })
+      return result
+    } catch (e) {
+      log(config, LogLevel.debug, e)
+      log(config, LogLevel.warning, "Error running beforeWrite command, returning original content")
+      return undefined
+    } finally {
+      await fs.rm(tmpPath, { force: true })
+      await fs.rm(rawTmpPath, { force: true })
+    }
+  }
+}
+
+async function prepareBeforeWriteCmd({
+  beforeWrite,
+  tmpPath,
+  content,
+  rawTmpPath,
+  rawContent,
+}: {
+  beforeWrite: string
+  tmpPath: string
+  content: Buffer
+  rawTmpPath: string
+  rawContent: Buffer
+}): Promise<string> {
+  let cmd: string = ""
+  const pathReg = /\{\{\s*path\s*\}\}/gi
+  const rawPathReg = /\{\{\s*rawpath\s*\}\}/gi
+  if (pathReg.test(beforeWrite)) {
+    await fs.writeFile(tmpPath, content)
+    cmd = beforeWrite.replaceAll(pathReg, tmpPath)
+  }
+  if (rawPathReg.test(beforeWrite)) {
+    await fs.writeFile(rawTmpPath, rawContent)
+    cmd = beforeWrite.replaceAll(rawPathReg, rawTmpPath)
+  }
+  if (!cmd) {
+    await fs.writeFile(tmpPath, content)
+    cmd = [beforeWrite, tmpPath].join(" ")
+  }
+  return cmd
+}