Merge pull request #48 from nippur72/code-in-comments

Code in comments

README.md

@@ -63,9 +63,10 @@ before going into TypeScript compiler:
 const opts = {
    DEBUG: true,
    version: 3,
-   "ifdef-verbose": true,          // add this for verbose output
-   "ifdef-triple-slash": false,    // add this to use double slash comment instead of default triple slash
-   "ifdef-fill-with-blanks": true  // add this to remove code with blank spaces instead of "//" comments 
+   "ifdef-verbose": true,                 // add this for verbose output
+   "ifdef-triple-slash": false,           // add this to use double slash comment instead of default triple slash
+   "ifdef-fill-with-blanks": true         // add this to remove code with blank spaces instead of "//" comments
+   "ifdef-uncomment-prefix": "// #code "  // add this to uncomment code starting with "// #code "
 };
 
 /* ... */ { 
@@ -96,6 +97,45 @@ in `example.ts`:
 /// #endif
 ```
 
+## Code in comments
+
+Often times writing `#if` ... `#else` ... `#endif` results in code that is not syntactically valid
+or does not pass the LINT check. A possible workaround is to hide such code in comments
+and let `ifdef-loader` uncomment it if it's part of the block that has to be included in the output.
+
+Example:
+
+The following code is invalid because the linter sees a double declaration of the `a` variable.
+```
+// #if DEBUG
+let a=1;
+// #else
+let a=2;
+// #endif
+```
+
+Using code in comments:
+```
+// #if DEBUG
+let a=1;
+// #else
+// #code let a=2;
+// #endif
+```
+The code is now under comment so it's ignored by the linter; but it's uncommented
+by `ifdef-loader` if the else branch has to be included in the output (that is when `DEBUG==false`).
+
+The `// #code ` string prefix can be changed and has to be explictly specified
+in the options object:
+
+```
+const opts = {
+   // ...
+   "ifdef-uncomment-prefix": "// #code ",
+   // ...
+};
+```
+
 ## License
 
 MIT
@@ -106,6 +146,8 @@ Contributions in the form of issues or pull requests are welcome.
 
 ## Changes
 
+- v2.3.0 added option `uncomment-prefix` to write code in comments allowing it to pass through linters and syntax checking
+
 - v2.2.0 added option `fill-with-blanks` for removing code with blank spaces instead of `//` comments
 
 - v2.1.0 added support for `#elif` clause.

ifdef-loader.ts

@@ -33,8 +33,14 @@ export = function(source: string, map) {
       delete data[fillWithBlanksFlag];
    }
 
+   const uncommentPrefixFlag = "ifdef-uncomment-prefix";
+   const uncommentPrefix = data[uncommentPrefixFlag];
+   if(uncommentPrefix !== undefined) {
+      delete data[uncommentPrefixFlag];
+   }
+
    try {
-      source = parse(source, data, verbose, tripleSlash, filePath, fillWithBlanks);
+      source = parse(source, data, verbose, tripleSlash, filePath, fillWithBlanks, uncommentPrefix);
       this.callback(null, source, map);
    } catch(err) {
       const errorMessage = `ifdef-loader error: ${err}`;

package.json

@@ -1,14 +1,14 @@
 {
   "name": "ifdef-loader",
-  "version": "2.2.1",
+  "version": "2.3.0",
   "description": "",
   "main": "ifdef-loader.js",
   "devDependencies": {
     "@types/jasmine": "^2.5.43",
     "@types/loader-utils": "^1.1.3",
-    "@types/node": "^7.0.5",
+    "@types/node": "^7.10.14",
     "jasmine": "^2.5.3",
-    "typescript": "^2.2.1",
+    "typescript": "^4.2.4",
     "webpack": "^3.5.5"
   },
   "scripts": {

preprocessor.ts

@@ -42,14 +42,17 @@ enum IfType { If, Elif }
 
 let useTripleSlash: boolean|undefined;
 let fillCharacter: string;
+let uncommentPrefix: string | undefined;
 
-export function parse(source: string, defs: OptionObject, verbose?: boolean, tripleSlash?: boolean, filePath?: string, fillWithBlanks?: boolean): string {
+export function parse(source: string, defs: OptionObject, verbose?: boolean, tripleSlash?: boolean, filePath?: string, fillWithBlanks?: boolean, uncommentPrefixString?: string): string {
    if(tripleSlash === undefined) tripleSlash = true;
    useTripleSlash = tripleSlash;
 
    if(fillWithBlanks === undefined) fillWithBlanks = false;
    fillCharacter = fillWithBlanks ? ' ' : '/';
 
+   uncommentPrefix = uncommentPrefixString;
+
    // early skip check: do not process file when no '#if' are contained
    if(source.indexOf('#if') === -1) return source;
 
@@ -202,6 +205,7 @@ function apply_if(lines: string[], ifBlock: IfBlock, defs: OptionObject, verbose
    if(includeRange != null) {      
       blank_code(lines, ifBlock.line_if, includeRange.from);   // blanks: #if ... "from"
       blank_code(lines, includeRange.to, ifBlock.line_endif);  // blanks: "to" ... #endif
+      reveal_code(lines, includeRange.from, includeRange.to);  // reveal: "from" ... "to"
    } else {
       blank_code(lines, ifBlock.line_if, ifBlock.line_endif);  // blanks: #if ... #endif
    }
@@ -253,3 +257,19 @@ function blank_code(lines: string[], start: number, end: number) {
       }
    }
 }
+
+function reveal_code(lines: string[], start: number, end: number) {
+   // early exit if no prefix is specifed
+   if(uncommentPrefix == undefined) return;
+
+   // create a regex capturing the line
+   let regex = new RegExp(`^(?<before>\s*${uncommentPrefix})(?<line>.*)$`);
+
+   // replace lines that match the uncomment prefix
+   for(let t=start; t<=end; t++) {
+      let r = regex.exec(lines[t]);
+      if(r!==null && r.groups!==undefined) {
+         lines[t] = " ".repeat(r.groups.before.length) + r.groups.line;
+      }
+   }
+}

spec/data/simple.fwb.out.js

@@ -14,4 +14,10 @@ var c=3;
 
 
 debug("or not");
-
+
+
+
+
+
+          let z=2;
+

spec/data/simple.in.js

@@ -14,4 +14,10 @@ loadVersion4();
 debug("hello");
 /// #else
 debug("or not");
-/// #endif
+/// #endif
+
+/// #if false
+let z=1;
+/// #else
+/// #code let z=2;
+/// #endif

spec/data/simple.out.js

@@ -14,4 +14,10 @@ var c=3;
 ///////////////
 /////////
 debug("or not");
-//////////
+//////////
+
+/////////////
+////////
+/////////
+          let z=2;
+//////////

spec/processSpec.ts

@@ -38,12 +38,13 @@ describe("files spec", ()=> {
    }));
 
    function check_spec(fillWithBlanks) {
+      const uncommentPrefix = "/// #code ";
       // checks spec files as terminating in CRLF (windows)
       fileSet.forEach( ({ input, output, output_fwb, actual, actual_fwb })=> {
          it(`works on ${input}`, ()=> {
             const tripleSlash = input.indexOf(".doubleslash.") == -1;
             const inFile = read(input);         
-            const actualFile = parse(inFile, defs, false, tripleSlash, undefined, fillWithBlanks);
+            const actualFile = parse(inFile, defs, false, tripleSlash, undefined, fillWithBlanks, uncommentPrefix);
             const expectedFile = read(fillWithBlanks ? output_fwb : output);            
             write(fillWithBlanks ? actual_fwb : actual, actualFile);
             expect(actualFile).toEqual(expectedFile);
@@ -55,7 +56,7 @@ describe("files spec", ()=> {
          it(`works on ${input}`, ()=> {
             const tripleSlash = input.indexOf(".doubleslash.") == -1;
             const inFile = removeCR(read(input));
-            const actualFile = parse(inFile, defs, false, tripleSlash, undefined, fillWithBlanks);
+            const actualFile = parse(inFile, defs, false, tripleSlash, undefined, fillWithBlanks, uncommentPrefix);
             const expectedFile = removeCR(read(fillWithBlanks ? output_fwb : output));            
             write(fillWithBlanks ? actualLF_fwb : actualLF, actualFile);
             expect(actualFile).toEqual(expectedFile);

tsconfig.json

@@ -2,7 +2,7 @@
     "compileOnSave": true,
     "compilerOptions": {
         "target": "es5",
-        "lib": ["es5", "es6"],
+        "lib": ["es5", "es6", "es2018"],
         "forceConsistentCasingInFileNames": false,
         "noFallthroughCasesInSwitch": true,
         "module": "commonjs",