Terse shorthand work start (#260)

* Terse shorthand work start

* All tests pass now

Author: kristoferbaxter

src/transformers/exports.ts

@@ -24,7 +24,13 @@ import {
 import { TransformSourceDescription, OutputOptions } from 'rollup';
 import { NamedDeclaration, DefaultDeclaration } from './parsing-utilities';
 import { isESMFormat } from '../options';
-import { Transform, TransformInterface, ExportClosureMapping, ExportDetails } from '../types';
+import {
+  Transform,
+  TransformInterface,
+  ExportClosureMapping,
+  ExportDetails,
+  Range,
+} from '../types';
 import MagicString from 'magic-string';
 import { parse, walk } from '../acorn';
 
@@ -230,8 +236,37 @@ export default class ExportTransform extends Transform implements TransformInter
                       if (exportFromCurrentSource) {
                         const { object: leftObject } = ancestor.expression.left;
                         if (leftObject.range) {
-                          const statement = inlineExport ? 'export var ' : 'var ';
-                          source.overwrite(leftObject.range[0], leftObject.range[1] + 1, statement);
+                          const { right } = ancestor.expression;
+                          switch (right.type) {
+                            case 'FunctionExpression':
+                              if (right.params.length > 0) {
+                                // FunctionExpression has parameters.
+                                source.overwrite(
+                                  (leftObject.range as Range)[0],
+                                  (right.params[0].range as Range)[0],
+                                  `${inlineExport ? 'export ' : ''}function ${
+                                    exportDetails.exported
+                                  }(`,
+                                );
+                              } else {
+                                source.overwrite(
+                                  (leftObject.range as Range)[0],
+                                  (right.body.range as Range)[0],
+                                  `${inlineExport ? 'export ' : ''}function ${
+                                    exportDetails.exported
+                                  }()`,
+                                );
+                              }
+                              break;
+                            default:
+                              const statement = inlineExport ? 'export var ' : 'var ';
+                              source.overwrite(
+                                leftObject.range[0],
+                                leftObject.range[1] + 1,
+                                statement,
+                              );
+                              break;
+                          }
                         }
                         if (exportDetails.local !== exportDetails.exported) {
                           exportDetails.local = exportDetails.exported;

test/arrow-function/fixtures/multiple-arguments.esm.es5.js

@@ -1 +1 @@
-export var multipleArguments=function(a,b){return console.log(a,b)};
+export function multipleArguments(a,b){return console.log(a,b)};

test/arrow-function/fixtures/single-argument.esm.es5.js

@@ -1 +1 @@
-export var singleArgument=function(a){return console.log(a)};
+export function singleArgument(a){return console.log(a)};

test/const-rename/fixtures/rename.esm.advanced.js

@@ -1 +1 @@
-let b=[3,4],c=[5,6];export var yes=function(a){return 0<=c.indexOf(a)&&0<=b.indexOf(a)};
+let b=[3,4],c=[5,6];export function yes(a){return 0<=c.indexOf(a)&&0<=b.indexOf(a)};

test/const-rename/fixtures/rename.esm.default.js

@@ -1 +1 @@
-let b=[3,4],c=[5,6];export var yes=function(a){return 0<=c.indexOf(a)&&0<=b.indexOf(a)};
+let b=[3,4],c=[5,6];export function yes(a){return 0<=c.indexOf(a)&&0<=b.indexOf(a)};

test/const-rename/fixtures/rename.esm.es5.js

@@ -1 +1 @@
-var b=[3,4],c=[5,6];export var yes=function(a){return 0<=c.indexOf(a)&&0<=b.indexOf(a)};
+var b=[3,4],c=[5,6];export function yes(a){return 0<=c.indexOf(a)&&0<=b.indexOf(a)};

test/export-all/fixtures/all.esm.advanced.js

@@ -1 +1 @@
-var export1=1;var export2=function(){return 2};export{export1,export2};
+var export1=1;function export2(){return 2};export{export1,export2};

test/export-all/fixtures/all.esm.default.js

@@ -1 +1 @@
-var export1=1;var export2=function(){return 2};export{export1,export2};
+var export1=1;function export2(){return 2};export{export1,export2};

test/export-all/fixtures/all.esm.es5.js

@@ -1 +1 @@
-var export1=1;var export2=function(){return 2};export{export1,export2};
+var export1=1;function export2(){return 2};export{export1,export2};

test/export-named/fixtures/multiple.esm.advanced.js

@@ -1 +1 @@
-var bar=function(){console.log(1)};var foo=1;export{bar,foo};
+function bar(){console.log(1)};var foo=1;export{bar,foo};