add snippet interface "async-await" (#1003)

Author: advance512

CHANGELOG.md

@@ -12,6 +12,7 @@ Please see [CONTRIBUTING.md](https://github.com/cucumber/cucumber/blob/master/CO
 * can now use glob patterns for selecting what features to run
 * update `--require` to support glob patterns
 * add `--require-module` to require node modules before support code is loaded
+* add snippet interface "async-await"
 
 #### Deprecations
 

docs/cli.md

@@ -88,7 +88,7 @@ Undefined steps snippets are printed in javascript using the callback interface
 ### Interface
 
 Override the snippet interface with `--format-options '{"snippetInterface": "<interface>"}'`.
-Valid interfaces are 'callback', 'generator', 'promise', or 'synchronous'.
+Valid interfaces are 'async-await', 'callback', 'generator', 'promise', or 'synchronous'.
 
 ### Syntax
 

docs/custom_snippet_syntaxes.md

@@ -2,7 +2,7 @@
 
 * See the [JavaScript syntax](/src/formatter/step_definition_snippet_builder/javascript_snippet_syntax.js) and the [custom snippet syntax](/features/step_definition_snippets_custom_syntax.feature) for examples.
   * Arguments passed to the constructor:
-    * `snippetInterface` - string equal to one of the following: 'callback', 'generator', 'promise', or 'synchronous'
+    * `snippetInterface` - string equal to one of the following: 'async-await', 'callback', 'generator', 'promise', or 'synchronous'
   * Arguments passed to `build` method:
     * An object with the following keys:
       * `comment`: a comment to be placed at the top of the function

features/step_definition_snippets_custom_syntax.feature

@@ -55,8 +55,9 @@ Feature: step definition snippets custom syntax
       """
 
     Examples:
-      | INTERFACE   | SNIPPET_PARAMETERS_AND_ARROW | SNIPPET_IMPLEMENTATION   |
-      | callback    | (done) ->                    | done null, 'pending' |
-      | generator   | ->                           | 'pending'                |
-      | promise     | ->                           | 'pending'                |
-      | synchronous | ->                           | 'pending'                |
+      | INTERFACE   | SNIPPET_PARAMETERS_AND_ARROW | SNIPPET_IMPLEMENTATION |
+      | callback    | (done) ->                    | done null, 'pending'   |
+      | generator   | ->                           | 'pending'              |
+      | promise     | ->                           | 'pending'              |
+      | async-await | ->                           | 'pending'              |
+      | synchronous | ->                           | 'pending'              |

features/step_definition_snippets_interfaces.feature

@@ -27,4 +27,5 @@ Feature: step definition snippets custom syntax
       | callback    | function (callback)                     | callback(null, 'pending') |
       | generator   | function *()                            | return 'pending'          |
       | promise     | function ()                             | return 'pending'          |
+      | async-await | async function ()                       | return 'pending'          |
       | synchronous | function ()                             | return 'pending'          |

src/formatter/step_definition_snippet_builder/javascript_snippet_syntax.js

@@ -7,7 +7,9 @@ export default class JavaScriptSnippetSyntax {
 
   build({ comment, generatedExpressions, functionName, stepParameterNames }) {
     let functionKeyword = 'function '
-    if (this.snippetInterface === 'generator') {
+    if (this.snippetInterface === 'async-await') {
+      functionKeyword = 'async ' + functionKeyword
+    } else if (this.snippetInterface === 'generator') {
       functionKeyword += '*'
     }