1 files changed, 0 insertions, 105 deletions
diff --git a/app/assets/javascripts/lib/utils/undo_stack.js b/app/assets/javascripts/lib/utils/undo_stack.js
deleted file mode 100644
index 6cfdc2a0a0f..00000000000
--- a/app/assets/javascripts/lib/utils/undo_stack.js
+++ /dev/null
@@ -1,105 +0,0 @@
-/**
- * UndoStack provides a custom implementation of an undo/redo engine. It was originally written for GitLab's Markdown editor (`gl_form.js`), whose rich text editing capabilities broke native browser undo/redo behaviour.
- *
- * UndoStack supports predictable undos/redos, debounced saves, maximum history length, and duplicate detection.
- *
- * Usage:
- *   - `stack = new UndoStack();`
- *   - Saves a state to the stack with `stack.save(state)`.
- *   - Get the current state with `stack.current()`.
- *   - Revert to the previous state with `stack.undo()`.
- *   - Redo a previous undo with `stack.redo()`;
- *   - Queue a future save with `stack.scheduleSave(state, delay)`. Useful for text editors.
- *   - See the full undo history in `stack.history`.
- */
-export default class UndoStack {
-  constructor(maxLength = 1000) {
-    this.clear();
-    this.maxLength = maxLength;
-
-    // If you're storing reference-types in the undo stack, you might want to
-    // reassign this property to some deep-equals function.
-    this.comparator = (a, b) => a === b;
-  }
-
-  current() {
-    if (this.cursor === -1) {
-      return undefined;
-    }
-    return this.history[this.cursor];
-  }
-
-  isEmpty() {
-    return this.history.length === 0;
-  }
-
-  clear() {
-    this.clearPending();
-    this.history = [];
-    this.cursor = -1;
-  }
-
-  save(state) {
-    this.clearPending();
-    if (this.comparator(state, this.current())) {
-      // Don't save state if it's the same as the current state
-      return;
-    }
-
-    this.history.length = this.cursor + 1;
-    this.history.push(state);
-    this.cursor += 1;
-
-    if (this.history.length > this.maxLength) {
-      this.history.shift();
-      this.cursor -= 1;
-    }
-  }
-
-  scheduleSave(state, delay = 1000) {
-    this.clearPending();
-    this.pendingState = state;
-    this.timeout = setTimeout(this.saveNow.bind(this), delay);
-  }
-
-  saveNow() {
-    // Persists scheduled saves immediately
-    this.save(this.pendingState);
-    this.clearPending();
-  }
-
-  clearPending() {
-    // Cancels any scheduled saves
-    if (this.timeout) {
-      clearTimeout(this.timeout);
-      delete this.timeout;
-      delete this.pendingState;
-    }
-  }
-
-  canUndo() {
-    return this.cursor > 0;
-  }
-
-  undo() {
-    this.clearPending();
-    if (!this.canUndo()) {
-      return undefined;
-    }
-    this.cursor -= 1;
-    return this.history[this.cursor];
-  }
-
-  canRedo() {
-    return this.cursor >= 0 && this.cursor < this.history.length - 1;
-  }
-
-  redo() {
-    this.clearPending();
-    if (!this.canRedo()) {
-      return undefined;
-    }
-    this.cursor += 1;
-    return this.history[this.cursor];
-  }
-}