extract attributes & improve help

scripts/content.js

@@ -25,17 +25,44 @@
 function extractData(itemsSelector, fieldSelectors) {
     return $(itemsSelector).toArray().map(
         item => fieldSelectors.map(
-            cls => $(item).find(cls).toArray().map(find => find.textContent.trim()).join('\n')
+            selector => {
+                let [cls, attr] = selector.split('@').slice(0, 2);
+                return $(item).find(cls).toArray().map(find => attr ? find[attr] : find.textContent.trim()).join('\n')
+            }
         )
     );
 }
 
 function extract(...args) {
-    let sig = `Invalid call args.
+    let sig = `
+# DataExtracter Help
+----------------------------
+
+## Signitures:
+----------------------------
 
 function extract(itemsSelector:string, fieldSelectors:string[])
 function extract(itemsSelector:string, fieldSelectors:string[], url:string, from:number, to:number, interval:number)
-function extract(itemsSelector:string, fieldSelectors:string, url:string, pages:number[])`;
+function extract(itemsSelector:string, fieldSelectors:string, url:string, pages:number[])
+
+## Examples:
+----------------------------
+
+### Extract current page
+extract(".list-item", ["a.title", "p.content"])
+
+### Extract multiple pages (1-10, interval 1)
+extract(".list-item", ["a.title", "p.content"],"http://sample.com/?pn=\${page}", 1, 10, 1)
+
+### Extract specified pages (1,3,5)
+extract(".list-item", ["a.title", "p.content"], "http://sample.com/?pn=\${page}", [1, 3, 5])
+
+## Advanced Examples:
+----------------------------
+
+### Extract link text and target (use 'selector@attribute')
+extract('.list-item', ['a.title', 'a.title@href'])
+`.trim();
     if (!testArgs(...args)) {
         console.log(sig);
         return;