Add support for the modifier keyword

packages/compat/src/resolver-transform.ts

@@ -78,6 +78,10 @@ export function makeResolverTransform(resolver: Resolver) {
             handleDynamicHelper(node.params[0], resolver, filename);
             return;
           }
+          if (node.path.original === 'modifier' && node.params.length > 0) {
+            handleDynamicModifier(node.params[0], resolver, filename);
+            return;
+          }
           resolver.resolveSubExpression(node.path.original, filename, node.path.loc);
         },
         MustacheStatement(node: ASTv1.MustacheStatement) {
@@ -341,3 +345,9 @@ function handleDynamicHelper(param: ASTv1.Node, resolver: Resolver, moduleName:
       resolver.resolveDynamicHelper({ type: 'other' }, moduleName, param.loc);
   }
 }
+
+function handleDynamicModifier(param: ASTv1.Expression, resolver: Resolver, moduleName: string): void {
+  if (param.type === 'StringLiteral') {
+    resolver.resolveDynamicModifier({ type: 'literal', path: param.value }, moduleName, param.loc);
+  }
+}

packages/compat/src/resolver.ts

@@ -859,6 +859,43 @@ export default class CompatResolver implements Resolver {
       );
     }
   }
+
+  resolveDynamicModifier(modifier: ComponentLocator, from: string, loc: Loc): Resolution | null {
+    if (!this.staticModifiersEnabled) {
+      return null;
+    }
+
+    if (modifier.type === 'literal') {
+      let modifierName = modifier.path;
+      if (builtInModifiers.includes(modifierName)) {
+        return null;
+      }
+
+      let found = this.tryModifier(modifierName, from);
+      if (found) {
+        return this.add(found, from);
+      }
+      return this.add(
+        {
+          type: 'error',
+          message: `Missing modifier`,
+          detail: modifierName,
+          loc,
+        },
+        from
+      );
+    } else {
+      return this.add(
+        {
+          type: 'error',
+          message: 'Unsafe dynamic modifier',
+          detail: `cannot statically analyze this expression`,
+          loc,
+        },
+        from
+      );
+    }
+  }
 }
 
 function humanReadableFile(root: string, file: string) {

packages/compat/tests/resolver.test.ts

@@ -531,6 +531,44 @@ describe('compat-resolver', function () {
       },
     ]);
   });
+  test('string literal passed to "modifier" keyword in content position', function () {
+    let findDependencies = configure({
+      staticModifiers: true,
+    });
+    givenFile('modifiers/add-listener.js');
+    expect(
+      findDependencies(
+        'templates/application.hbs',
+        `<button {{(modifier "add-listener" "click" this.handleClick)}}>Test</button>`
+      )
+    ).toEqual([
+      {
+        path: '../modifiers/add-listener.js',
+        runtimeName: 'the-app/modifiers/add-listener',
+      },
+    ]);
+  });
+  test('modifier currying using the "modifier" keyword', function () {
+    let findDependencies = configure({ staticModifiers: true });
+    givenFile('modifiers/add-listener.js');
+    expect(
+      findDependencies(
+        'templates/application.hbs',
+        `
+        {{#let (modifier "add-listener") as |addListener|}}
+          {{#let (modifier addListener "click") as |addClickListener|}}
+            <button {{addClickListener this.handleClick}}>Test</button>
+          {{/let}}
+        {{/let}}
+        `
+      )
+    ).toEqual([
+      {
+        path: '../modifiers/add-listener.js',
+        runtimeName: 'the-app/modifiers/add-listener',
+      },
+    ]);
+  });
   test('built-in components are ignored when used with the component helper', function () {
     let findDependencies = configure({
       staticComponents: true,
@@ -561,6 +599,20 @@ describe('compat-resolver', function () {
       )
     ).toEqual([]);
   });
+  test('built-in modifiers are ignored when used with the "modifier" keyword', function () {
+    let findDependencies = configure({
+      staticModifiers: true,
+    });
+    expect(
+      findDependencies(
+        'templates/application.hbs',
+        `
+      <button {{(modifier "on" "click" this.handleClick)}}>Test</button>
+      <button {{(modifier "action" "handleClick")}}>Test</button>
+    `
+      )
+    ).toEqual([]);
+  });
   test('component helper with direct addon package reference', function () {
     let findDependencies = configure({
       staticComponents: true,
@@ -681,6 +733,25 @@ describe('compat-resolver', function () {
       },
     ]);
   });
+  test('string literal passed to "modifier" keyword in helper position', function () {
+    let findDependencies = configure({ staticModifiers: true });
+    givenFile('modifiers/add-listener.js');
+    expect(
+      findDependencies(
+        'templates/application.hbs',
+        `
+        {{#let (modifier "add-listener" "click") as |addClickListener|}}
+          <button {{addClickListener this.handleClick}}>Test</button>
+        {{/let}}
+        `
+      )
+    ).toEqual([
+      {
+        path: '../modifiers/add-listener.js',
+        runtimeName: 'the-app/modifiers/add-listener',
+      },
+    ]);
+  });
   test('string literal passed to component helper fails to resolve', function () {
     let findDependencies = configure({ staticComponents: true });
     givenFile('components/my-thing.js');
@@ -694,6 +765,15 @@ describe('compat-resolver', function () {
       findDependencies('templates/application.hbs', `{{helper "hello-world"}}`);
     }).toThrow(new RegExp(`Missing helper: hello-world in templates/application.hbs`));
   });
+  test('string literal passed to "modifier" keyword fails to resolve', function () {
+    let findDependencies = configure({ staticModifiers: true });
+    expect(() => {
+      findDependencies(
+        'templates/application.hbs',
+        `<button {{(modifier "add-listener" "click" this.handleClick)}}>Test</button>`
+      );
+    }).toThrow(new RegExp(`Missing modifier: add-listener in templates/application.hbs`));
+  });
   test('string literal passed to component helper fails to resolve when staticComponents is off', function () {
     let findDependencies = configure({ staticComponents: false });
     givenFile('components/my-thing.js');
@@ -703,6 +783,16 @@ describe('compat-resolver', function () {
     let findDependencies = configure({ staticHelpers: false });
     expect(findDependencies('templates/application.hbs', `{{helper "hello-world"}}`)).toEqual([]);
   });
+  test('string literal passed to "modifier" keyword fails to resolve when staticModifiers is off', function () {
+    let findDependencies = configure({ staticModifiers: false });
+    givenFile('modifiers/add-listener.js');
+    expect(
+      findDependencies(
+        'templates/application.hbs',
+        `<button {{(modifier "add-listener" "click" this.handleClick)}}>Test</button>`
+      )
+    ).toEqual([]);
+  });
   test('dynamic component helper error in content position', function () {
     let findDependencies = configure({ staticComponents: true });
     givenFile('components/hello-world.js');
@@ -925,7 +1015,7 @@ describe('compat-resolver', function () {
     ]);
   });
   test('ignores builtins', function () {
-    let findDependencies = configure({ staticHelpers: true, staticComponents: true });
+    let findDependencies = configure({ staticHelpers: true, staticComponents: true, staticModifiers: true });
     expect(
       findDependencies(
         'templates/application.hbs',
@@ -1778,6 +1868,11 @@ describe('compat-resolver', function () {
     );
   });
 
+  test('ignores any non-string-literal in "modifier" keyword', function () {
+    let findDependencies = configure({ staticModifiers: true });
+    expect(findDependencies('templates/application.hbs', `<div {{(modifier this.which)}}></div>`)).toEqual([]);
+  });
+
   test('trusts inline ensure-safe-component helper', function () {
     let findDependencies = configure({ staticComponents: true });
     expect(findDependencies('templates/application.hbs', `{{component (ensure-safe-component this.which) }}`)).toEqual(