helper function $

manifest.json

@@ -21,7 +21,8 @@
       "scripts/background/result.js",
       "scripts/background/signiture.js",
       "scripts/background/actions.js",
-      "scripts/background/extractor.js"
+      "scripts/background/extractor.js",
+      "scripts/background/helpers.js"
     ],
     "persistent": false
   },

readme.md

@@ -5,7 +5,7 @@ DataExtracter helps you quickly extract data from any web pages.
 
 All you need to do is:
 
-- Find out the selectors (JQuery selectors) for target data
+- Find out the selectors for target data
 - Type scripts in the console of `extension backgroud page`, as introduced bellow.
 
  ![](images/console.png)
@@ -14,40 +14,40 @@ All you need to do is:
 
 Extract current page
 ```js
-new Extractor().task(".list-item", ["a.title", "p.content"]).start();
+$('.item', ['a', 'a@href']);
 ```
 
 Extract multiple pages (1-10, interval 1)
 
 ```js
-new Extractor().task(".list-item", ["a.title", "p.content"],"http://sample.com/?pn=${page}", 1, 10, 1).start();
+$('.item', ['a', 'a@href'],"http://sample.com/?pn=${page}", 1, 10, 1);
 ```
 
 Extract multiple urls (list)
 
 ```js
-new Extractor().task(".list-item", ["a.title", "p.content"],["http://sample.com/abc","http://sample.com/xyz"]).start();
+$('.item', ['a', 'a@href'],["http://sample.com/abc","http://sample.com/xyz"]);
 ```
 
 Extract specified pages (1,3,5)
 
 ```js
-new Extractor().task(".list-item", ["a.title", "p.content"], "http://sample.com/?pn=${page}", [1, 3, 5]).start();
+$('.item', ['a', 'a@href'], "http://sample.com/?pn=${page}", [1, 3, 5]);
 ```
 
-## Extractor.task() Signitures
+## Task Call Signitures
 
 ```ts
-// a task extracting data from current page
-task(itemsSelector:string, fieldSelectors:string[])
-// a task extracting data from a range of pages
-task(itemsSelector:string, fieldSelectors:string[], urlTemplate:string, from:number, to:number, interval:number)
-// a task extracting data from a list of pages
-task(itemsSelector:string, fieldSelectors:string, urlTemplate:string, pages:number[])
-// a task extracting data from a list of pages
-task(itemsSelector:string, fieldSelectors:string[], urls:string[])
-// a task extracting data of urls which extracted from last task result
-task(itemsSelector:string, fieldSelectors:string[], urls:ExtractResult)
+// extract data from current page
+function (itemsSelector:string, fieldSelectors:string[])
+// extract data from a range of pages
+function (itemsSelector:string, fieldSelectors:string[], urlTemplate:string, from:number, to:number, interval:number)
+// extract data from a list of pages
+function (itemsSelector:string, fieldSelectors:string, urlTemplate:string, pages:number[])
+// extract data from a list of pages
+function (itemsSelector:string, fieldSelectors:string[], urls:string[])
+// extract data of urls which extracted from last task result
+function (itemsSelector:string, fieldSelectors:string[], urls:ExtractResult)
 ```
 
 ## Advanced Usage
@@ -65,7 +65,7 @@ The only way to stop tasks before its finish, is `Closing the host tab`.
 e.g.: link text and target (use 'selector@attribute')
 
 ```js
-new Extractor().task('.list-item', ['a.title', 'a.title@href']).start();
+new Extractor().task('.item', ['a', 'a@href']).start();
 ```
 
 ### Use Task Chain.
@@ -74,7 +74,7 @@ e.g.: Collect links from `http://sample.com/abc`, then, Extract data of each lin
 
 ```js
 new Extractor()
-    .task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
+    .task('.search-list-item', ['a@href'], ["http://sample.com/abc"])
     .task('list-item', ["a.title", "p.content"])
     .start();
 ```
@@ -85,7 +85,7 @@ To a multiple task (chain) Extractor `e`:
 
 ```js
 e = new Extractor()
-e.task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
+e.task('.search-list-item', ['a@href'], ["http://sample.com/abc"])
     .task('list-item', ["a.title", "p.content"])
     .start();
 ```
@@ -114,7 +114,7 @@ Here we have 2 tasks:
 
 ```js
 e = new Extractor()
-e.task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
+e.task('.search-list-item', ['a@href'], ["http://sample.com/abc"])
     .task('list-item', ["a.title", "p.content"])
     .start();
 ```

scripts/background/extractor.js

@@ -15,7 +15,6 @@ class Extractor {
     task(...args) {
         if (!testArgs(...args)) {
             console.log(`Invalid task arguments: ${argsToString(...args)}\n\n${signitures}\n`);
-            // break call chain to avoid unexpected task running
             return this;
         }
         // given >2 arguments means the task specifies target page, 
@@ -31,6 +30,7 @@ class Extractor {
     clear() {
         this._tasks = [];
         this._results = [];
+        return this;
     }
     /**
      * Start the task chain.
@@ -64,6 +64,7 @@ class Extractor {
             result => {
                 this._results[this._tasks[this._tasks.length - 1]] = result;
                 this._running = false;
+                console.log("Tasks are all done.")
                 this.save();
             }
         ).catch(err => {
@@ -122,9 +123,16 @@ class Extractor {
             console.log(`No result for task #${taskid}. Forget to call ".start()"?`);
             return;
         }
-        if (confirm(
-                `Click confirm to download if the sample data looks good (${result.data.length} items)：\n\n${result.toString(50) || "- Empty -"}`
-            )) {
+        if (result.data.length <= 1) { // 1 for selector headers
+            console.log(`No result for task #${taskid}. Forget to call ".start()"?`);
+            return;
+        }
+        let msg = `
+Please confirm to download (${result.data.length - 1} items)：
+
+${result.toString(50) || "- Empty -"}
+`.trim();
+        if (confirm(msg)) {
             saveFile(result, "text/csv");
         }
     }

scripts/background/helpers.js

@@ -0,0 +1,3 @@
+function $(...args) {
+    return new Extractor().task(...args).start();
+}

scripts/background/signiture.js

@@ -1,17 +1,21 @@
 const signitures = `
 ## Usage
-new Extractor().task(...args).task(...args).start();
+// single task
+$(...args);
+// managed task chains
+e = new Extractor();
+e.task(...args).task(...args).start();
 
-## Extractor.task() Signitures:
-function(itemsSelector:string, fieldSelectors:string[])
-function(itemsSelector:string, fieldSelectors:string[], url:string, from:number, to:number, interval:number)
-function(itemsSelector:string, fieldSelectors:string[], url:string, pages:number[])
-function(itemsSelector:string, fieldSelectors:string[], urls:string[])
+## Task Call Signitures:
+function(itemsSelector:string, fieldSelectors:string[]);
+function(itemsSelector:string, fieldSelectors:string[], url:string, from:number, to:number, interval:number);
+function(itemsSelector:string, fieldSelectors:string[], url:string, pages:number[]);
+function(itemsSelector:string, fieldSelectors:string[], urls:string[]);
 
 ## Example:
 // extract all links text & url under '.item' elements
 // use 'selector@attr' to get attribute of the field elements
-new Extractor().task(".item", ["a", "a@href"]).start();
+$(".item", ["a", "a@href"]);
 
 ## See Detailed Help:
 https://git.jebbs.co/jebbs/data-extracter-extesion