Use typescript to parse source files

Fixes #54

.vscode/settings.json

@@ -1,3 +1,4 @@
 {
-    "vsicons.presets.angular": false
+    "vsicons.presets.angular": false,
+    "prettier.printWidth": 100
 }

index.js

@@ -1,59 +1,178 @@
-
 var loaderUtils = require("loader-utils");
+var ts = require("typescript");
 
-// using: regex, capture groups, and capture group variables.
-var templateUrlRegex = /templateUrl\s*:(\s*['"`](.*?)['"`]\s*([,}]))/gm;
-var stylesRegex = /styleUrls *:(\s*\[[^\]]*?\])/g;
-var stringRegex = /(['`"])((?:[^\\]\\\1|.)*?)\1/g;
+function calculateTemplateUrlReplacement(propertyAssignment, replacedPropertyName) {
+  return [
+    {
+      start: propertyAssignment.name.getStart(),
+      end: propertyAssignment.name.getEnd(),
+      replacement: replacedPropertyName
+    },
+    constructUrlReplacement(propertyAssignment.initializer)
+  ];
+}
 
-function replaceStringsWithRequires(string) {
-  return string.replace(stringRegex, function (match, quote, url) {
-    if (url.charAt(0) !== ".") {
-      url = "./" + url;
+function calculateStyleUrlsReplacement(propertyAssignment, replacedPropertyName) {
+  var styleUrlsReplacements = [];
+  for (var i = 0; i < propertyAssignment.initializer.elements.length; i++) {
+    styleUrlsReplacements.push(constructUrlReplacement(propertyAssignment.initializer.elements[i]));
+  }
+  return [
+    {
+      start: propertyAssignment.name.getStart(),
+      end: propertyAssignment.name.getEnd(),
+      replacement: replacedPropertyName
     }
-    return "require('" + url + "')";
-  });
+  ].concat(styleUrlsReplacements);
 }
 
-module.exports = function(source, sourcemap) {
+function constructUrlReplacement(element) {
+  var delimiter = "'";
+  if (element.kind === ts.SyntaxKind.FirstTemplateToken) {
+    delimiter = "`";
+  }
+  var url = element.text.replace(/(['"\\])/g, "\\$&");
+  if (url.charAt(0) !== ".") {
+    url = "./" + url;
+  }
+
+  return {
+    start: element.getStart(),
+    end: element.getEnd(),
+    replacement: "require(" + delimiter + url + delimiter + ")";
+  };
+}
+
+function isTemplateUrlProperty(propertyAssignment) {
+  return (
+    propertyAssignment.name.kind === ts.SyntaxKind.Identifier &&
+    propertyAssignment.name.text === "templateUrl" &&
+    (propertyAssignment.initializer.kind === ts.SyntaxKind.StringLiteral ||
+      propertyAssignment.initializer.kind === ts.SyntaxKind.FirstTemplateToken)
+  );
+}
+
+function isStyleUrlsPropery(propertyAssignment) {
+  return (
+    propertyAssignment.name.kind === ts.SyntaxKind.Identifier &&
+    propertyAssignment.name.text === "styleUrls" &&
+    propertyAssignment.initializer.kind === ts.SyntaxKind.ArrayLiteralExpression &&
+    propertyAssignment.initializer.elements.every(function(element) {
+      return (
+        element.kind === ts.SyntaxKind.StringLiteral ||
+        element.kind === ts.SyntaxKind.FirstTemplateToken
+      );
+    })
+  );
+}
+
+function flatten(prev, current) {
+  return prev.concat(current);
+}
 
+function findeReplacements(node, templateReplacement, styleReplacement) {
+  var positions = [];
+
+  calculateReplacements(node);
+
+  function calculateReplacements(node) {
+    switch (node.kind) {
+      // search only for class declarations
+      case ts.SyntaxKind.ClassDeclaration:
+        if (node.decorators && node.decorators.length > 0) {
+          // filter for all decorators containing a component decorator
+          var replacementPositions = node.decorators
+            .filter(function(decorator) {
+              return (
+                decorator.expression.kind === ts.SyntaxKind.CallExpression &&
+                decorator.expression.expression.kind === ts.SyntaxKind.Identifier &&
+                decorator.expression.expression.text === "Component" &&
+                decorator.expression.arguments.length > 0
+              );
+            })
+            .map(function(decorator) {
+              return decorator.expression.arguments[0];
+            })
+            // the argument must be a literal expression
+            .filter(function(argument) {
+              return (argument.kind = ts.SyntaxKind.ObjectLiteralExpression);
+            })
+            .map(function(literalExpression) {
+              return literalExpression.properties;
+            })
+            .reduce(flatten, [])
+            // filter for property assignments
+            .filter(function(properties) {
+              return properties.kind === ts.SyntaxKind.PropertyAssignment;
+            })
+            // only filter for property assignments with the text templateUrl or styleUrls
+            .filter(function(propertyAssignment) {
+              return (
+                isTemplateUrlProperty(propertyAssignment) || isStyleUrlsPropery(propertyAssignment)
+              );
+            })
+            .map(function(propertyAssignment) {
+              if (propertyAssignment.name.text === "templateUrl") {
+                return calculateTemplateUrlReplacement(propertyAssignment, templateReplacement);
+              } else {
+                return calculateStyleUrlsReplacement(propertyAssignment, styleReplacement);
+              }
+            })
+            .reduce(flatten, []);
+          positions = positions.concat(replacementPositions);
+        }
+        break;
+    }
+
+    return ts.forEachChild(node, calculateReplacements);
+  }
+
+  return positions;
+}
+
+module.exports = function(source, sourcemap) {
   var config = {};
   var query = loaderUtils.parseQuery(this.query);
-  var styleProperty = 'styles';
-  var templateProperty = 'template';
+  var styleProperty = "styles";
+  var templateProperty = "template";
 
   if (this.options != null) {
-    Object.assign(config, this.options['angular2TemplateLoader']);
+    Object.assign(config, this.options["angular2TemplateLoader"]);
   }
 
   Object.assign(config, query);
 
   if (config.keepUrl === true) {
-      styleProperty = 'styleUrls';
-      templateProperty = 'templateUrl';
+    styleProperty = "styleUrls";
+    templateProperty = "templateUrl";
   }
 
-    // Not cacheable during unit tests;
+  // Not cacheable during unit tests;
   this.cacheable && this.cacheable();
 
-  var newSource = source.replace(templateUrlRegex, function (match, url) {
-                 // replace: templateUrl: './path/to/template.html'
-                 // with: template: require('./path/to/template.html')
-                 // or: templateUrl: require('./path/to/template.html')
-                 // if `keepUrl` query parameter is set to true.
-                 return templateProperty + ":" + replaceStringsWithRequires(url);
-               })
-               .replace(stylesRegex, function (match, urls) {
-                 // replace: stylesUrl: ['./foo.css', "./baz.css", "./index.component.css"]
-                 // with: styles: [require('./foo.css'), require("./baz.css"), require("./index.component.css")]
-                 // or: styleUrls: [require('./foo.css'), require("./baz.css"), require("./index.component.css")]
-                 // if `keepUrl` query parameter is set to true.
-                 return styleProperty + ":" + replaceStringsWithRequires(urls);
-               });
+  var fileName = this.resourcePath;
+
+  var sourceFile = ts.createSourceFile(
+    fileName,
+    source,
+    ts.ScriptTarget.ES6,
+    /*setParentNodes */ true
+  );
+
+  var positions = findeReplacements(sourceFile, templateProperty, styleProperty);
+
+  var newSource = source;
+
+  for (var i = positions.length - 1; i >= 0; i--) {
+    var pos = positions[i];
+    var prefix = newSource.substring(0, pos.start);
+    var postfix = newSource.substring(pos.end);
+    newSource = prefix + pos.replacement + postfix;
+  }
 
   // Support for tests
   if (this.callback) {
-    this.callback(null, newSource, sourcemap)
+    this.callback(null, newSource, sourcemap);
   } else {
     return newSource;
   }

package.json

@@ -35,6 +35,7 @@
     "should": "^9.0.0"
   },
   "dependencies": {
-    "loader-utils": "^0.2.15"
+    "loader-utils": "^0.2.15",
+    "typescript": "^2.3.4"
   }
 }

test/fixtures/component_with_template_literals.js

@@ -0,0 +1,12 @@
+var componentWithTemplateLiterals = `
+  import {Component} from '@angular/core';
+
+  @Component({
+    selector: 'test-component',
+    templateUrl: \`./some/path/to/file.html\`,
+    styleUrls: [\`./app/css/styles.css\`]
+  })
+  export class TestComponent {}
+`;
+
+module.exports = componentWithTemplateLiterals;

test/fixtures/index.js

@@ -5,6 +5,7 @@ var componentWithoutRelPeriodSlash = require('./component_without_relative_perio
 var componentWithSpacing = require('./component_with_spacing.js');
 var componentWithSingleLineDecorator = require('./component_with_single_line_decorator.js');
 var componentWithTemplateUrlEndingBySpace = require('./component_with_template_url_ending_by_space.js');
+var componentWithTemplateLiterals = require('./component_with_template_literals.js');
 
 exports.simpleAngularTestComponentFileStringSimple = sampleAngularComponentSimpleFixture;
 exports.componentWithQuoteInUrls = componentWithQuoteInUrls;
@@ -13,3 +14,4 @@ exports.componentWithoutRelPeriodSlash = componentWithoutRelPeriodSlash;
 exports.componentWithSpacing = componentWithSpacing;
 exports.componentWithSingleLineDecorator = componentWithSingleLineDecorator;
 exports.componentWithTemplateUrlEndingBySpace = componentWithTemplateUrlEndingBySpace;
+exports.componentWithTemplateLiterals = componentWithTemplateLiterals;