fix: show some colors in logs

src/copy-addon.ts

@@ -2,6 +2,7 @@ import { sys, Program } from 'typescript'
 import { resolve, relative, normalize } from 'path'
 import { relativeToCWD } from './path.utils'
 import { cp } from './fs.utils'
+import { red } from './log.utils'
 
 /**
  * Copy non-typescript files to `outDir`.
@@ -13,14 +14,12 @@ export default function copyOtherFiles(program: Program, emittedFiles: string[]
 	const { outDir, listEmittedFiles } = program.getCompilerOptions()
 
 	if (outDir == null) {
-		console.warn('Cannot copy: you must define `outDir` in the compiler options')
+		console.error(red('Cannot copy: you must define `outDir` in the compiler options'))
 		return
 	}
 
 	const srcDir = program.getCommonSourceDirectory()
-	if (!srcDir) {
-		throw Error('Cannot copy: issue with internal typescript method `getCommonSourceDirectory`')
-	}
+	if (!srcDir) throw Error('Cannot copy: issue with internal typescript method `getCommonSourceDirectory`')
 
 	const otherFiles = matchAllFilesBut(srcDir, ['**/*.ts'])
 	const copiedFiles: string[] = [] // Track copied files to list them later if needed

src/index.ts

@@ -1,6 +1,7 @@
 import ts from 'typescript'
 import { CreateProgramFromConfigOptions, TsConfig, EmitOptions, BuildOptions } from './interfaces'
 import { ensureAbsolutePath } from './path.utils'
+import { logDiagnostics, red, yellow, green } from './log.utils'
 import cleanTargets from './clean-addon'
 import copyOtherFiles from './copy-addon'
 
@@ -85,30 +86,13 @@ export function emit(program: ts.Program, { basePath, clean, copyOtherToOutDir,
 	const allDiagnostics = ts.getPreEmitDiagnostics(program).concat(diagnostics)
 	logDiagnostics(allDiagnostics, betterDiagnostics)
 
-	if (!options.noEmit && emitSkipped) throw Error('Compilation failed')
-
-	if (copyOtherToOutDir) copyOtherFiles(program, emittedFiles)
-
-	if (allDiagnostics.length) console.log(`Compilation done with ${allDiagnostics.length} errors`)
-	else console.log('Compilation successful')
-}
-
-/**
- * Log compiler diagnostics to stderr.
- * @internal
- */
-function logDiagnostics(diagnostics: ts.Diagnostic[], better = false) {
-	if (!diagnostics.length) return
-
-	const formatHost: ts.FormatDiagnosticsHost = {
-		getCanonicalFileName: (path) => path,
-		getCurrentDirectory: ts.sys.getCurrentDirectory,
-		getNewLine: () => ts.sys.newLine,
+	if (!options.noEmit && emitSkipped) {
+		console.error(red('Compilation failed'))
+		return
 	}
 
-	const message = better
-		? ts.formatDiagnosticsWithColorAndContext(diagnostics, formatHost)
-		: ts.formatDiagnostics(diagnostics, formatHost)
+	if (copyOtherToOutDir) copyOtherFiles(program, emittedFiles)
 
-	console.warn(message)
+	if (allDiagnostics.length) console.log(yellow(`Compilation done with ${allDiagnostics.length} errors`))
+	else console.log(green('Compilation successful'))
 }

src/log.utils.ts

@@ -0,0 +1,93 @@
+import ts from 'typescript'
+
+/**
+ * Log compiler diagnostics to stderr.
+ * @internal
+ */
+export function logDiagnostics(diagnostics: ts.Diagnostic[], better = false) {
+	if (!diagnostics.length) return
+
+	const formatHost: ts.FormatDiagnosticsHost = {
+		getCanonicalFileName: (path) => path,
+		getCurrentDirectory: ts.sys.getCurrentDirectory,
+		getNewLine: () => ts.sys.newLine,
+	}
+
+	const message = better
+		? ts.formatDiagnosticsWithColorAndContext(diagnostics, formatHost)
+		: ts.formatDiagnostics(diagnostics, formatHost)
+
+	console.warn(message)
+}
+
+/**
+ * @internal
+ */
+export function grey(text: string) {
+	return formatColor(text, EscapeSequence.Grey)
+}
+
+/**
+ * @internal
+ */
+export function red(text: string) {
+	return formatColor(text, EscapeSequence.Red)
+}
+
+/**
+ * @internal
+ */
+export function green(text: string) {
+	return formatColor(text, EscapeSequence.Green)
+}
+
+/**
+ * @internal
+ */
+export function yellow(text: string) {
+	return formatColor(text, EscapeSequence.Yellow)
+}
+
+/**
+ * @internal
+ */
+export function blue(text: string) {
+	return formatColor(text, EscapeSequence.Blue)
+}
+
+/**
+ * @internal
+ */
+export function magenta(text: string) {
+	return formatColor(text, EscapeSequence.Magenta)
+}
+
+/**
+ * @internal
+ */
+export function cyan(text: string) {
+	return formatColor(text, EscapeSequence.Cyan)
+}
+
+/**
+ * Apply foreground color to text.
+ * @internal
+ */
+function formatColor(text: string, color: EscapeSequence) {
+	return color + text + EscapeSequence.Reset
+}
+
+/**
+ * Foreground color escape sequences.
+ * Taken from https://github.com/microsoft/TypeScript/blob/v3.5.3/src/compiler/program.ts#L368
+ */
+enum EscapeSequence {
+	Grey = '\u001b[90m',
+	Red = '\u001b[91m',
+	Green = '\u001b[92m',
+	Yellow = '\u001b[93m',
+	Blue = '\u001b[94m',
+	Magenta = '\u001b[95m',
+	Cyan = '\u001b[96m',
+	Reset = '\u001b[0m',
+}

src/ts-internals.d.ts

@@ -29,6 +29,24 @@ declare module 'typescript' {
 		readonly directories: ReadonlyArray<string>
 	}
 
+	/**
+	 * @see https://github.com/microsoft/TypeScript/blob/v3.5.3/src/compiler/utilities.ts#L7087-L7105
+	 */
+	function createCompilerDiagnostic(message: DiagnosticMessage): Diagnostic
+
+	/**
+	 * @see https://github.com/microsoft/TypeScript/blob/v3.5.3/src/compiler/utilities.ts#L7107-L7117
+	 */
+	function createCompilerDiagnosticFromMessageChain(chain: DiagnosticMessageChain): Diagnostic
+
+	enum ForegroundColorEscapeSequences {
+		Grey,
+		Red,
+		Yellow,
+		Blue,
+		Cyan,
+	}
+
 	interface Program {
 		/**
 		 * @see https://github.com/microsoft/TypeScript/blob/v3.5.3/src/compiler/program.ts#L982-L1006