Add liveDev feature

Fix: #63

README.md

@@ -381,6 +381,29 @@ This would export a file at `./src/foo.ts` as `./foo`, and a file
 at `./src/utils/bar.ts` as `./utils/bar`, but would ignore a file
 at `./internal/private.ts`.
 
+### Live Dev
+
+Set `"liveDev": true` in the tshy config in `package.json` to
+build in link mode. In this mode, the files are hard-linked into
+place in the `dist` folder, so that edits are immediately visible.
+
+This is particularly beneficial in monorepo projects, where
+workspaces may be edited in parallel, and so it's handy to have
+changes reflected in real time without a rebuild.
+
+Of course, tools that can't handle TypeScript will have a problem
+with this, so any generic `node` program will not be able to run
+your code. For this reason:
+
+- `liveDev` is always disabled when the `npm_command` environment
+  variable is `'publish'` or `'pack'`. In these situations, your
+  code is being built for public consumption, and must be
+  compiled.
+- Code in dist will not be able to be loaded in the node repl
+  unless you run it with a loader, such as `node --import=tsx`.
+- Because it links files into place, a rebuild _is_ required when
+  a file is added or removed.
+
 ### Package `#imports`
 
 You can use `"imports"` in your package.json, and it will be

src/build-live-commonjs.ts

@@ -0,0 +1,43 @@
+import chalk from 'chalk'
+import { linkSync, mkdirSync } from 'node:fs'
+import { dirname } from 'node:path'
+import { relative, resolve } from 'node:path/posix'
+import config from './config.js'
+import * as console from './console.js'
+import ifExist from './if-exist.js'
+import polyfills from './polyfills.js'
+import setFolderDialect from './set-folder-dialect.js'
+import sources from './sources.js'
+import './tsconfig.js'
+
+const { commonjsDialects = [] } = config
+
+// don't actually do a build, just link files into places.
+export const buildLiveCommonJS = () => {
+  for (const d of ['commonjs', ...commonjsDialects]) {
+    const pf = polyfills.get(d === 'commonjs' ? 'cjs' : d)
+    console.debug(chalk.cyan.dim('linking ' + d))
+    for (const s of sources) {
+      const source = s.substring('./src/'.length)
+      const target = resolve(`.tshy-build/${d}/${source}`)
+      mkdirSync(dirname(target), { recursive: true })
+      linkSync(s, target)
+    }
+    setFolderDialect('.tshy-build/' + d, 'commonjs')
+    for (const [override, orig] of pf?.map.entries() ?? []) {
+      const stemFrom = resolve(
+        `.tshy-build/${d}`,
+        relative(resolve('src'), resolve(override))
+      ).replace(/\.cts$/, '')
+      const stemTo = resolve(
+        `.tshy-build/${d}`,
+        relative(resolve('src'), resolve(orig))
+      ).replace(/\.tsx?$/, '')
+      ifExist.unlink(`${stemTo}.js.map`)
+      ifExist.unlink(`${stemTo}.d.ts.map`)
+      ifExist.rename(`${stemFrom}.cjs`, `${stemTo}.js`)
+      ifExist.rename(`${stemFrom}.d.cts`, `${stemTo}.d.ts`)
+    }
+    console.error(chalk.cyan.bold('linked commonjs'))
+  }
+}

src/build-live-esm.ts

@@ -0,0 +1,41 @@
+import chalk from 'chalk'
+import { linkSync, mkdirSync } from 'node:fs'
+import { dirname, relative, resolve } from 'node:path'
+import config from './config.js'
+import * as console from './console.js'
+import ifExist from './if-exist.js'
+import polyfills from './polyfills.js'
+import setFolderDialect from './set-folder-dialect.js'
+import sources from './sources.js'
+import './tsconfig.js'
+
+const { esmDialects = [] } = config
+
+export const buildLiveESM = () => {
+  for (const d of ['esm', ...esmDialects]) {
+    const pf = polyfills.get(d)
+    console.debug(chalk.cyan.dim('linking ' + d))
+    for (const s of sources) {
+      const source = s.substring('./src/'.length)
+      const target = resolve(`.tshy-build/${d}/${source}`)
+      mkdirSync(dirname(target), { recursive: true })
+      linkSync(s, target)
+    }
+    setFolderDialect('.tshy-build/' + d, 'esm')
+    for (const [override, orig] of pf?.map.entries() ?? []) {
+      const stemFrom = resolve(
+        `.tshy-build/${d}`,
+        relative(resolve('src'), resolve(override))
+      ).replace(/\.mts$/, '')
+      const stemTo = resolve(
+        `.tshy-build/${d}`,
+        relative(resolve('src'), resolve(orig))
+      ).replace(/\.tsx?$/, '')
+      ifExist.unlink(`${stemTo}.js.map`)
+      ifExist.unlink(`${stemTo}.d.ts.map`)
+      ifExist.rename(`${stemFrom}.mjs`, `${stemTo}.js`)
+      ifExist.rename(`${stemFrom}.d.mts`, `${stemTo}.d.ts`)
+    }
+    console.error(chalk.cyan.bold('linked ' + d))
+  }
+}

src/build.ts

@@ -1,4 +1,5 @@
 import chalk from 'chalk'
+import config from './config.js'
 import { syncContentSync } from 'sync-content'
 import bins from './bins.js'
 import { buildCommonJS } from './build-commonjs.js'
@@ -18,14 +19,22 @@ import {
   unlink as unlinkImports,
 } from './unbuilt-imports.js'
 import writePackage from './write-package.js'
+import { buildLiveESM } from './build-live-esm.js'
+import { buildLiveCommonJS } from './build-live-commonjs.js'
 
 export default async () => {
   cleanBuildTmp()
 
   linkSelfDep(pkg, 'src')
   await linkImports(pkg, 'src')
-  if (dialects.includes('esm')) buildESM()
-  if (dialects.includes('commonjs')) buildCommonJS()
+  const liveDev =
+    config.liveDev &&
+    process.env.npm_command !== 'publish' &&
+    process.env.npm_command !== 'pack'
+  const esm = liveDev ? buildLiveESM : buildESM
+  const commonjs = liveDev ? buildLiveCommonJS : buildCommonJS
+  if (dialects.includes('esm')) esm()
+  if (dialects.includes('commonjs')) commonjs()
   await unlinkImports(pkg, 'src')
   unlinkSelfDep(pkg, 'src')
 

src/config.ts

@@ -40,7 +40,8 @@ const validConfig = (e: any): e is TshyConfigMaybeGlobExports =>
   (e.exclude === undefined || validExclude(e.exclude)) &&
   validExtraDialects(e) &&
   validBoolean(e, 'selfLink') &&
-  validBoolean(e, 'main')
+  validBoolean(e, 'main') &&
+  validBoolean(e, 'liveDev')
 
 const match = (e: string, pattern: Minimatch[]): boolean =>
   pattern.some(m => m.match(e))

src/exports.ts

@@ -14,6 +14,11 @@ import { resolveExport } from './resolve-export.js'
 import { Package, TshyConfig, TshyExport } from './types.js'
 const { esmDialects = [], commonjsDialects = [] } = config
 
+const liveDev =
+  config.liveDev &&
+  process.env.npm_command !== 'publish' &&
+  process.env.npm_command !== 'pack'
+
 const getTargetForDialectCondition = <T extends string>(
   s: string | TshyExport | undefined | null,
   dialect: T,
@@ -35,13 +40,17 @@ const getTargetForDialectCondition = <T extends string>(
     const xts = type === 'commonjs' ? '.mts' : '.cts'
     if (s.endsWith(xts)) return undefined
     const pf = dialect === 'commonjs' ? 'cjs' : dialect
+    const rel = relative(
+      resolve('./src'),
+      resolve(polyfills.get(pf)?.map.get(s) ?? s)
+    )
+    const target = liveDev
+      ? rel
+      : rel.replace(/\.([mc]?)tsx?$/, '.$1js')
     return !s || !s.startsWith('./src/')
       ? s
       : dialects.includes(type)
-      ? `./dist/${dialect}/${relative(
-          resolve('./src'),
-          resolve(polyfills.get(pf)?.map.get(s) ?? s)
-        ).replace(/\.([mc]?)tsx?$/, '.$1js')}`
+      ? `./dist/${dialect}/${target}`
       : undefined
   }
   return resolveExport(s, [condition])
@@ -106,10 +115,12 @@ const getExports = (
           polyfills
         )
         if (target) {
-          exp[d] = {
-            types: target.replace(/\.js$/, '.d.ts'),
-            default: target,
-          }
+          exp[d] = liveDev
+            ? target
+            : {
+                types: target.replace(/\.js$/, '.d.ts'),
+                default: target,
+              }
         }
       }
     }
@@ -124,25 +135,31 @@ const getExports = (
           polyfills
         )
         if (target) {
-          exp[d] = {
-            types: target.replace(/\.js$/, '.d.ts'),
-            default: target,
-          }
+          exp[d] = liveDev
+            ? target
+            : {
+                types: target.replace(/\.js$/, '.d.ts'),
+                default: target,
+              }
         }
       }
     }
     // put the default import/require after all the other special ones.
     if (impTarget) {
-      exp.import = {
-        types: impTarget.replace(/\.(m?)js$/, '.d.$1ts'),
-        default: impTarget,
-      }
+      exp.import = liveDev
+        ? impTarget
+        : {
+            types: impTarget.replace(/\.(m?)js$/, '.d.$1ts'),
+            default: impTarget,
+          }
     }
     if (reqTarget) {
-      exp.require = {
-        types: reqTarget.replace(/\.(c?)js$/, '.d.$1ts'),
-        default: reqTarget,
-      }
+      exp.require = liveDev
+        ? reqTarget
+        : {
+            types: reqTarget.replace(/\.(c?)js$/, '.d.$1ts'),
+            default: reqTarget,
+          }
     }
   }
   return e

src/types.ts

@@ -13,6 +13,7 @@ export type TshyConfigMaybeGlobExports = {
   esmDialects?: string[]
   project?: string
   exclude?: string[]
+  liveDev?: boolean
 }
 
 export type TshyConfig = TshyConfigMaybeGlobExports & {

tap-snapshots/test/build-live-commonjs.ts.test.cjs

@@ -0,0 +1,16 @@
+/* IMPORTANT
+ * This snapshot file is auto-generated, but designed for humans.
+ * It should be checked into source control and tracked carefully.
+ * Re-generate by setting TAP_SNAPSHOT=1 and running tests.
+ * Make sure to inspect the output below.  Do not ignore changes!
+ */
+'use strict'
+exports[`test/build-live-commonjs.ts > TAP > commonjs live dev build > must match snapshot 1`] = `
+Array [
+  "blah-blah.cts",
+  "blah-cjs.cts",
+  "blah.ts",
+  "index.ts",
+  "package.json",
+]
+`

tap-snapshots/test/build-live-esm.ts.test.cjs

@@ -0,0 +1,16 @@
+/* IMPORTANT
+ * This snapshot file is auto-generated, but designed for humans.
+ * It should be checked into source control and tracked carefully.
+ * Re-generate by setting TAP_SNAPSHOT=1 and running tests.
+ * Make sure to inspect the output below.  Do not ignore changes!
+ */
+'use strict'
+exports[`test/build-live-esm.ts > TAP > esm live dev build > must match snapshot 1`] = `
+Array [
+  "blah-blah.mts",
+  "blah-cjs.cts",
+  "blah.ts",
+  "index.ts",
+  "package.json",
+]
+`