jsParse: Make getCompletions() asynchronous

Part of the possible completions involves evaluating the part
of the passed in text that looks like an object, so that we
can query it for properties.

Using a Function or eval() for that means that we can only
complete text that does not use `await`. To get over that
limitation, evaluate the text in an AsyncFunction instead.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2842>

diff --git a/js/misc/jsParse.js b/js/misc/jsParse.js
index 18ce703982a0cf5a91ba99e89efa1f334f5044d6..e55d69a30df12496b19cee181831ac8abfc6254b 100644 (file)
--- a/js/misc/jsParse.js
+++ b/js/misc/jsParse.js
@@ -1,6 +1,8 @@
 /* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
 /* exported getCompletions, getCommonPrefix, getDeclaredConstants */
 
+const AsyncFunction = async function () {}.constructor;
+
 /**
  * Returns a list of potential completions for text. Completions either
  * follow a dot (e.g. foo.ba -> bar) or they are picked from globalCompletionList (e.g. fo -> foo)
@@ -13,7 +15,7 @@
  * @param {string} commandHeader
  * @param {readonly string[]} [globalCompletionList]
  */
-function getCompletions(text, commandHeader, globalCompletionList) {
+async function getCompletions(text, commandHeader, globalCompletionList) {
     let methods = [];
     let expr_, base;
     let attrHead = '';
@@ -29,7 +31,7 @@ function getCompletions(text, commandHeader, globalCompletionList) {
         if (matches) {
             [expr_, base, attrHead] = matches;
 
-            methods = getPropertyNamesFromExpression(base, commandHeader).filter(
+            methods = (await getPropertyNamesFromExpression(base, commandHeader)).filter(
                 attr => attr.slice(0, attrHead.length) === attrHead);
         }
 
@@ -193,13 +195,13 @@ function getAllProps(obj) {
  * @param {string} expr
  * @param {string=} commandHeader
  */
-function getPropertyNamesFromExpression(expr, commandHeader = '') {
+async function getPropertyNamesFromExpression(expr, commandHeader = '') {
     let obj = {};
     if (!isUnsafeExpression(expr)) {
         try {
-            const lines = expr.split(';');
+            const lines = expr.split('\n');
             lines.push(`return ${lines.pop()}`);
-            obj = Function(commandHeader + lines.join(';'))();
+            obj = await AsyncFunction(commandHeader + lines.join(';'))();
         } catch (e) {
             return [];
         }