Bug 1750505 - [devtools] Remove lodash uniqBy usage. r=ochameau

Differential Revision: https://phabricator.services.mozilla.com/D136165

devtools/client/debugger/src/actions/breakpoints/breakpointPositions.js

@@ -7,7 +7,6 @@ import {
   isGeneratedId,
   originalToGeneratedId,
 } from "devtools-source-map";
-import { uniqBy } from "lodash";
 
 import {
   getSource,
@@ -44,8 +43,24 @@ function filterBySource(positions, sourceId) {
   return positions.filter(position => position.location.sourceId == sourceId);
 }
 
+/**
+ * Merge positions that refer to duplicated positions.
+ * Some sourcemaped positions might refer to the exact same source/line/column triple.
+ *
+ * @param {Array<{location, generatedLocation}>} positions: List of possible breakable positions
+ * @returns {Array<{location, generatedLocation}>} A new, filtered array.
+ */
 function filterByUniqLocation(positions) {
-  return uniqBy(positions, ({ location }) => makeBreakpointId(location));
+  const handledBreakpointIds = new Set();
+  return positions.filter(({ location }) => {
+    const breakpointId = makeBreakpointId(location);
+    if (handledBreakpointIds.has(breakpointId)) {
+      return false;
+    }
+
+    handledBreakpointIds.add(breakpointId);
+    return true;
+  });
 }
 
 function convertToList(results, source) {

devtools/client/debugger/src/selectors/visibleBreakpoints.js

@@ -3,7 +3,6 @@
  * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
 
 import { createSelector } from "reselect";
-import { uniqBy } from "lodash";
 
 import { getBreakpointsList } from "../reducers/breakpoints";
 import { getSelectedSource } from "../reducers/sources";
@@ -41,9 +40,16 @@ export const getFirstVisibleBreakpoints = createSelector(
       return [];
     }
 
-    return uniqBy(
-      sortSelectedBreakpoints(breakpoints, selectedSource),
-      bp => getSelectedLocation(bp, selectedSource).line
-    );
+    // Filter the array so it only return the first breakpoint when there's multiple
+    // breakpoints on the same line.
+    const handledLines = new Set();
+    return sortSelectedBreakpoints(breakpoints, selectedSource).filter(bp => {
+      const line = getSelectedLocation(bp, selectedSource).line;
+      if (handledLines.has(line)) {
+        return false;
+      }
+      handledLines.add(line);
+      return true;
+    });
   }
 );