evanw · Dec 23, 2020 · Dec 23, 2020 · Dec 23, 2020 · Dec 23, 2020 · Dec 29, 2020
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## Proposal
+
+* Add `--remove-console` option that avoids print console calls to target
+* Add `--remove-debugger` option that avoids print debugger statement to target
+* Add `--debug-tool=...` enable debug tool in target ([more info](https://github.com/evanw/esbuild/blob/master/docs/debugtool.md))
+* Add `--removedebug-tool=...` remove debug tool from target([more info](https://github.com/evanw/esbuild/blob/master/docs/debugtool.md))
 ## Unreleased
 
 * Mark `import.meta` as supported in node 10.4+ ([#626](https://github.com/evanw/esbuild/issues/626))

diff --git a/cmd/esbuild/main.go b/cmd/esbuild/main.go
@@ -78,7 +78,11 @@ var helpText = func(colors logger.Colors) string {
   --sources-content=false   Omit "sourcesContent" in generated source maps
   --tree-shaking=...        Set to "ignore-annotations" to work with packages
                             that have incorrect tree-shaking annotations
-  --tsconfig=...            Use this tsconfig.json file instead of other ones
+	--tsconfig=...            Use this tsconfig.json file instead of other ones
+	--remove--console         Removes console calls
+	--remove--debugger        Removes debugger statements
+	--debugTool=...           debugTool
+	--removeDebugTool         remove debugTool
   --version                 Print the current version and exit (` + esbuildVersion + `)
 
 ` + colors.Bold + `Examples:` + colors.Default + `

diff --git a/docs/debugtool.md b/docs/debugtool.md
@@ -0,0 +1,158 @@
+# Debug tool 
+Debug Tool helps you insert debug code and easily to remove it when deploy to production
+
+### LOG
+Similar to console.log but logs also identifiers and source code position
+```javascript
+// app.js
+import { DEBUGTOOL } from './debug'
+function sum(a,b) {
+  DEBUGTOOL.LOG(a,b);
+  → console.log('a='+ a, 'b='+ b, ' at app.js:3:3');
+  return a+b;
+}
+```
+### ASSERT
+Similar to assert but logs also identifier and source code position
+```javascript
+// app.js
+import { DEBUGTOOL } from './debug'
+function sum(a,b) {
+  DEBUGTOOL.ASSERT(a>0,b>0)
+  → if (!(a>0)) throw new Error('assert a>0 at app.js:3:3');
+  → if (!(b>0)) throw new Error('assert b>0 at app.js:3:3');
+  return a+b
+}
+```
+### TRACE 
+Useful for test local variables on test units. It's not for production mode.
+```javascript
+// lib.js
+import { DEBUGTOOL } from './debug'
+function quadraticEquation(a,b,c) {
+  const delta = b*b - 4*a*c; ← b² – 4ac
+  DEBUGTOOL.TRACE(a, b, c, delta)
+  → tracelog.push('a=' +a + ' b=' + b +' c=' + c + ' delta=' + delta);
+  if (delta<0) return null
+  const x1 = (-b + sqrt(delta)) / (2*a)
+  const x2 = (-b - sqrt(delta)) / (2*a)
+  return {x1, x2}
+}
+// test.js
+import { DEBUGTOOL } from './debug'
+it(()=>{
+  DEBUGTOOL.RESET() 
+  → tracelog = [] // traceLog is a global
+  const result = quadraticEquation(1, 8, -9) // x² + 8x - 9 = 0
+  const deltaWasTraced = DEBUGTOOL.ASSERT(/delta=100/} 
+  → const deltaWasTraced = traceLog.some(l=>/delta=100/.test(l)))
+  except(deltaWasTraced).toBe(true)
+  except(DEBUGTOOL.HISTORY()).toBe('a=1 b=8 c=-9 delta=100')
+  ...
+})
+```
+## Using with esbuilder
+
+## CLI
+
+In development or test mode
+```
+./node_modules/.bin/esbuild app.jsx --bundle --debug-tool=DEBUGTOOL --outfile=out.js
+```
+
+In production mode
+```
+./node_modules/.bin/esbuild app.jsx --bundle --remove-debug-tool=DEBUGTOOL --outfile=out.js
+```
+
+##### API
+In development or test mode
+```
+require('esbuild').buildSync({
+  entryPoints: ['in.ts'],
+  outfile: 'out.js',
+  debugTool: 'DEBUGTOOL',
+})
+```
+
+In production mode
+```
+require('esbuild').buildSync({
+  entryPoints: ['in.ts'],
+  outfile: 'out.js',
+  removeDebugTool: 'DEBUGTOOL',
+})
+```
+
+### why use debugtoos
+- Sugar syntax alternative for `if (process.env.NODE_ENV === 'development')` 
+- tests can take benefits from historical debugging
+- No globals
+- Compatible syntax
+
+### debug.js module
+You will need a debug module, like that but customized to your needs.
+
+See samples in https://github.com/thr0w/babel-plugin-debug-tools
+
+```javascript
+
+var traceLog = [];
+var DEBUGTOOL = {
+  LOG(...args) {
+    console.log(...args.slice(1).map((a) => JSON.stringify(a)));
+  },
+  ASSERT(...args) {
+    const loc = args[0];
+    for (let i = 1; i < args.length; i++) {
+      const arg = args[i];
+      if (Array.isArray(arg)) {
+        if (!arg[1])
+          throw new Error("ASSERT FAIL: " + arg[0] + formatLoc(loc) + (arg[2] ? JSON.stringify(arg[2]) : ""));
+      } else if (typeof arg === "string") {
+        if (!traceLog.some((l) => l.indexOf(arg) > -1))
+          throw new Error("NOT FOUND IN HISTORY: " + arg + formatLoc(loc));
+      } else {
+        if (!traceLog.some((l) => arg.test(l)))
+          throw new Error("NOT FOUND IN HISTORY: " + arg.toString() + " at " + formatLoc(loc));
+      }
+    }
+  },
+  RESET() {
+    traceLog = [];
+  },
+  HISTORY() {
+    return traceLog.join("\n");
+  },
+  TRACE(...args) {
+    traceLog.push(formatArgs(args.slice(1), 0));
+  },
+  CHECK(regExp) {
+    return traceLog.some((l) => regExp.test(l));
+  }
+};
+function formatLoc(loc) {
+  if (loc)
+    return " at " + (loc.filename || "") + ":" + loc.line + ":" + loc.column + " ";
+  return "";
+}
+function formatArg(arg) {
+  if (typeof arg === "string")
+    return arg;
+  return JSON.stringify(arg);
+}
+function formatArgs(args, sLoc) {
+  const flatArgs = [];
+  for (let i = 0; i < args.length - sLoc; i++) {
+    const arg = args[i];
+    if (Array.isArray(arg) && arg.length == 2) {
+      flatArgs.push(formatArg(arg[0]) + ": " + formatArg(arg[1]));
+    } else
+      flatArgs.push(formatArg(arg));
+  }
+  if (sLoc)
+    flatArgs.push(formatArg(formatLoc(args[args.length - 1])));
+  return flatArgs.join(" ");
+}
+
+```
diff --git a/internal/bundler/bundler_transpile_test.go b/internal/bundler/bundler_transpile_test.go
@@ -0,0 +1,179 @@
+package bundler
+
+import (
+	"testing"
+
+	"github.com/evanw/esbuild/internal/config"
+)
+
+var transpile_suite = suite{
+	name: "transpile",
+}
+
+func TestNoRemoveConsole(t *testing.T) {
+	transpile_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/entry.ts": `
+				const a=1;
+				console.log(a)
+			`,
+		},
+		entryPaths: []string{"/entry.ts"},
+		options: config.Options{
+			Mode:          config.ModeBundle,
+			AbsOutputFile: "/out.js",
+		},
+	})
+}
+
+func TestRemoveConsole(t *testing.T) {
+	transpile_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/entry.ts": `
+				const a=1;
+				console.log(a)
+			`,
+		},
+		entryPaths: []string{"/entry.ts"},
+		options: config.Options{
+			Mode:          config.ModeBundle,
+			RemoveConsole: true,
+			AbsOutputFile: "/out.js",
+		},
+	})
+}
+func TestNoRemoveDebbuger(t *testing.T) {
+	transpile_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/entry.ts": `
+				const a=1;
+				debugger;
+				console.log(a)
+			`,
+		},
+		entryPaths: []string{"/entry.ts"},
+		options: config.Options{
+			Mode:          config.ModeBundle,
+			AbsOutputFile: "/out.js",
+		},
+	})
+}
+
+func TestRemoveDebbuger(t *testing.T) {
+	transpile_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/entry.ts": `
+				const a=1;
+				debugger;
+				console.log(a);
+			`,
+		},
+		entryPaths: []string{"/entry.ts"},
+		options: config.Options{
+			Mode:           config.ModeBundle,
+			RemoveDebugger: true,
+			AbsOutputFile:  "/out.js",
+		},
+	})
+}
+
+func TestDebugToolsBhaskara(t *testing.T) {
+	transpile_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/bhaskara.js": `
+			import { BHASKARA } from './debug'
+
+			export function quadraticEquation(a, b, c) {
+				BHASKARA.ASSERT(a !== 0)
+				const delta = b * b - 4 * a * c; // b² – 4ac
+				BHASKARA.TRACE(a, b, c, delta)
+				if (delta < 0) return null
+				const x1 = (-b + Math.sqrt(delta)) / (2 * a)
+				const x2 = (-b - Math.sqrt(delta)) / (2 * a)
+				BHASKARA.TRACE(x1, x2)
+				return { x1, x2 }
+			}
+			`,
+			"/bhaskara.test.js": `
+			import { quadraticEquation } from './bhaskara'
+			import { BHASKARA } from './debug'
+			
+			test('x² + 8x - 9 = 0', () => {
+				BHASKARA.RESET()
+				BHASKARA.ASSERT(typeof quadraticEquation === 'function')
+				const { x1, x2 } = quadraticEquation(1, 8, -9)
+				BHASKARA.ASSERT(/delta: 100/, x1 === 1, x2 === -9)
+				expect(BHASKARA.HISTORY()).toEqual('a: 1 b: 8 c: -9 delta: 100\nx1: 1 x2: -9')
+			});			
+			`,
+			"/debug.js": `
+			let traceLog = [];
+
+			export const BHASKARA = {
+				LOG(...args) {
+					console.log(...args.slice(1).map( (a)=>JSON.stringify(a)));
+				},
+				ASSERT(...args) {
+					const loc = args[0]
+					for (let i = 1; i < args.length; i++) {
+						const arg = args[i]
+						if (Array.isArray(arg)) {
+							if (!arg[1]) throw new Error(
+								'ASSERT FAIL: ' + arg[0] + formatLoc(loc) +
+								(arg[2] ? JSON.stringify(arg[2]) : '')
+							);
+						} else if (typeof arg === 'string') {
+							if (!traceLog.some(l => l.indexOf(arg) > -1))
+								throw new Error('NOT FOUND IN HISTORY: ' + arg + formatLoc(loc))
+						} else {
+							if (!traceLog.some(l => arg.test(l)))
+								throw new Error('NOT FOUND IN HISTORY: ' + arg.toString() + ' at ' + formatLoc(loc))
+						}
+					}
+				},
+				RESET() {
+					traceLog = [];
+				},
+				HISTORY() {
+					return traceLog.join('\n')
+				},
+				TRACE(...args) {
+					traceLog.push(formatArgs(args.slice(1), 0));
+				},
+				CHECK(regExp) {
+					return traceLog.some(l => regExp.test(l))
+				}
+			};
+			
+			function formatLoc(loc) {
+				if (loc)
+					return ' at ' + (loc.filename || '') + ':' + loc.line + ':' + loc.column + ' ';
+				return ''
+			}
+			function formatArg(arg) {
+				if (typeof arg === 'string') return arg
+				return JSON.stringify(arg)
+			}
+			function formatArgs(args, sLoc) {
+				const flatArgs = []
+				for (let i = 0; i < args.length - sLoc; i++) {
+					const arg = args[i]
+					if (Array.isArray(arg) && arg.length == 2) {
+						flatArgs.push(formatArg(arg[0]) + ': ' + formatArg(arg[1]))
+					}
+					else flatArgs.push(formatArg(arg))
+				}
+				if (sLoc)
+					flatArgs.push(formatArg(formatLoc(args[args.length - 1])))
+				return flatArgs.join(' ')
+			}
+			`,
+		},
+		entryPaths: []string{"/bhaskara.test.js"},
+		options: config.Options{
+			Mode:          config.ModeBundle,
+			DebugTool:     "BHASKARA",
+			AbsOutputFile: "/out.js",
+		},
+	})
+}
diff --git a/internal/bundler/linker.go b/internal/bundler/linker.go
@@ -3276,6 +3276,10 @@ func (c *linkerContext) generateCodeForFileInChunkJS(
 		Indent:              indent,
 		OutputFormat:        c.options.OutputFormat,
 		RemoveWhitespace:    c.options.RemoveWhitespace,
+		RemoveConsole:       c.options.RemoveConsole,
+		RemoveDebugger:      c.options.RemoveDebugger,
+		DebugTool:           c.options.DebugTool,
+		RemoveDebugTool:     c.options.RemoveDebugTool,
 		MangleSyntax:        c.options.MangleSyntax,
 		ASCIIOnly:           c.options.ASCIIOnly,
 		ToModuleRef:         toModuleRef,