added autoInject, adapted from #608

2 files changed, 48 insertions, 0 deletions

diff --git a/lib/autoInject.js b/lib/autoInject.js
new file mode 100644
index 0000000..1b6fea4
--- /dev/null
+++ b/lib/autoInject.js
@@ -0,0 +1,45 @@
+import auto from './auto';
+import forOwn from 'lodash/forOwn';
+import arrayMap from 'lodash/_arrayMap';
+import isArray from 'lodash/isArray';
+
+var argsRegex =  /^function\s*[^\(]*\(\s*([^\)]*)\)/m;
+
+function parseParams(func) {
+    return  func.toString().match(argsRegex)[1].split(/\s*\,\s*/);
+}
+
+export default function autoInject(tasks, callback) {
+    var newTasks = {};
+
+    forOwn(tasks, function (taskFn, key) {
+        var params;
+
+        if (isArray(taskFn)) {
+            params = [...taskFn];
+            taskFn = params.pop();
+
+            newTasks[key] = [...params].concat(newTask);
+        } else if (taskFn.length === 0) {
+            throw new Error("autoInject task functions require explicit parameters.");
+        } else if (taskFn.length === 1) {
+            // no dependencies
+            newTasks[key] = taskFn;
+        } else {
+            params = parseParams(taskFn);
+            params.pop();
+
+            newTasks[key] = [...params].concat(newTask);
+
+        }
+
+        function newTask(results, taskCb) {
+            var newArgs = arrayMap(params, function (name) {
+                return results[name];
+            });
+            taskFn(...newArgs.concat(taskCb));
+        }
+    });
+
+    auto(newTasks, callback);
+}
diff --git a/lib/index.js b/lib/index.js
index 300491d..3db4064 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -5,6 +5,7 @@ import applyEachSeries from './applyEachSeries';
 import apply from './apply';
 import asyncify from './asyncify';
 import auto from './auto';
+import autoInject from './autoInject';
 import cargo from './cargo';
 import compose from './compose';
 import concat from './concat';
@@ -71,6 +72,7 @@ export default {
     apply: apply,
     asyncify: asyncify,
     auto: auto,
+    autoInject: autoInject,
     cargo: cargo,
     compose: compose,
     concat: concat,
@@ -155,6 +157,7 @@ export {
     apply as apply,
     asyncify as asyncify,
     auto as auto,
+    autoInject as autoInject,
     cargo as cargo,
     compose as compose,
     concat as concat,