js doc and code optimize

scripts/content.js

@@ -1,15 +1,23 @@
 chrome.runtime.onMessage.addListener(
     function (request, sender, sendResponse) {
         // console.log(request);
-        if (request.from == "DataExtracter:Extract") {
+        switch (request.from) {
-            let data = extractData(request.itemsSelector, request.fieldSelectors);
+            case "DataExtracter:Extract":
-            if (sendResponse) sendResponse(data);
+                let data = extractData(request.itemsSelector, request.fieldSelectors);
-        } else if (request.from == "DataExtracter:GotoUrl") {
+                if (sendResponse) sendResponse(data);
-            window.location.replace(request.url);
+                break;
-        } else if (request.from == "DataExtracter:ReportIn") {
+            case "DataExtracter:GotoUrl":
-            if (sendResponse) sendResponse(request.from);
+                window.location.replace(request.url);
-        } else if (request.from == "DataExtracter:QueryUrl") {
+                if (sendResponse) sendResponse(request.url);
-            if (sendResponse) sendResponse(window.location.href);
+                break;
+            case "DataExtracter:ReportIn":
+                if (sendResponse) sendResponse(request.from);
+                break;
+            case "DataExtracter:QueryUrl":
+                if (sendResponse) sendResponse(window.location.href);
+                break;
+            default:
+                break;
         }
     }
 );
@@ -49,12 +57,9 @@ function extract(itemsSelector:string, fieldSelectors:string, url:string, pages:
 }
 
 function testArgs(...args) {
-
     if (args.length < 2) return false;
-
     if (args.length == 2)
         return (args[0] && args[1] && (typeof args[0] == "string") && (args[1] instanceof Array))
-
     let urls = [];
     if (args.length > 2) return (typeof args[2] == "string") && (
         (args[3] instanceof Array) ||

scripts/extract.js

@@ -1,5 +1,10 @@
-// function extract(itemsSelector, fieldSelectors, url, from, to, interval)
+/**
-// function extract(itemsSelector, fieldSelectors, url, pages)
+ * Extract data from current tab / multiple urls.
+ * @param {string} itemsSelector items selectors for selecting items (data rows)
+ * @param {Array<string>} fieldSelectors fields selectors for selecting fields (data columns) under each item
+ * @param {string} url url template to generate urls by filling with page numers.
+ * @param {...number} args page numers, either [from, to, interval] or [...pages]
+ */
 function extract(itemsSelector, fieldSelectors, url, ...args) {
     let urls = [];
     if (url) {
@@ -65,6 +70,13 @@ function redirectTab(tab, url) {
         .then(() => reportIn(tab));
 }
 
+/**
+ * extract data in from the target tab, usually used to detect if the content script is ready.
+ * @param {any} tab target tab
+ * @param {string} itemsSelector items selectors for selecting items (data rows)
+ * @param {Array<string>} fieldSelectors fields selectors for selecting fields (data columns) under each item
+ * @returns {Promise<string[]>} a promise of extracted data
+ */
 function extractData(tab, itemsSelector, fieldSelectors) {
     let req = {
         from: "DataExtracter:Extract",
@@ -76,6 +88,11 @@ function extractData(tab, itemsSelector, fieldSelectors) {
     return sendMessageAndDetect(tab, req, cond, failMsg);
 }
 
+/**
+ * get report in from the target tab, usually used to detect if the content script is ready.
+ * @param {any} tab target tab
+ * @returns {Promise<string>} a promise of the report in message
+ */
 function reportIn(tab) {
     let req = {
         from: "DataExtracter:ReportIn"
@@ -85,6 +102,12 @@ function reportIn(tab) {
     return sendMessageAndDetect(tab, req, cond, failMsg);
 }
 
+/**
+ * get the url of the target tab
+ * @param {any} tab target tab
+ * @param {string} urlExcluded if specified, queryUrl resolves only when response not equals to urlExcluded
+ * @returns {Promise<string>} a promise of the url
+ */
 function queryUrl(tab, urlExcluded) {
     let req = {
         from: "DataExtracter:QueryUrl"
@@ -96,13 +119,13 @@ function queryUrl(tab, urlExcluded) {
 
 /**
  * Repeatedly sending a message to target tab until the response is detected good.
- * The response is returned with the Promise.
+ * @param {object} tab the table where to send the message
- * @param {chrome.tab} tab the table where to send the message
  * @param {object} req the request data.
  * @param {function} cond success condition function, r:any=>boolean
  * @param {string} failMsg message when failed after time out
  * @param {number} failedTimeOut fail time out
  * @param {number} detectInterval interval for detecting
+ * @return {Promise} a promise of the response.
  */
 function sendMessageAndDetect(tab, req, cond, failMsg, failedTimeOut, detectInterval) {
     failedTimeOut = failedTimeOut || 10000;