1 files changed, 133 insertions, 0 deletions
diff --git a/devtools/client/debugger/src/reducers/expressions.js b/devtools/client/debugger/src/reducers/expressions.js
new file mode 100644
index 0000000000..d8589eca84
--- /dev/null
+++ b/devtools/client/debugger/src/reducers/expressions.js
@@ -0,0 +1,133 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+/**
+ * Expressions reducer
+ * @module reducers/expressions
+ */
+
+import { prefs } from "../utils/prefs";
+
+export const initialExpressionState = () => ({
+  expressions: restoreExpressions(),
+  expressionError: false,
+  autocompleteMatches: {},
+  currentAutocompleteInput: null,
+});
+
+function update(state = initialExpressionState(), action) {
+  switch (action.type) {
+    case "ADD_EXPRESSION":
+      if (action.expressionError) {
+        return { ...state, expressionError: !!action.expressionError };
+      }
+      return appendExpressionToList(state, {
+        input: action.input,
+        value: null,
+        updating: true,
+      });
+
+    case "UPDATE_EXPRESSION":
+      const key = action.expression.input;
+      const newState = updateExpressionInList(state, key, {
+        input: action.input,
+        value: null,
+        updating: true,
+      });
+
+      return { ...newState, expressionError: !!action.expressionError };
+
+    case "EVALUATE_EXPRESSION":
+      return updateExpressionInList(state, action.input, {
+        input: action.input,
+        value: action.value,
+        updating: false,
+      });
+
+    case "EVALUATE_EXPRESSIONS":
+      const { inputs, results } = action;
+
+      return inputs.reduce(
+        (_state, input, index) =>
+          updateExpressionInList(_state, input, {
+            input,
+            value: results[index],
+            updating: false,
+          }),
+        state
+      );
+
+    case "DELETE_EXPRESSION":
+      return deleteExpression(state, action.input);
+
+    case "CLEAR_EXPRESSION_ERROR":
+      return { ...state, expressionError: false };
+
+    case "AUTOCOMPLETE":
+      const { matchProp, matches } = action.result;
+
+      return {
+        ...state,
+        currentAutocompleteInput: matchProp,
+        autocompleteMatches: {
+          ...state.autocompleteMatches,
+          [matchProp]: matches,
+        },
+      };
+
+    case "CLEAR_AUTOCOMPLETE":
+      return {
+        ...state,
+        autocompleteMatches: {},
+        currentAutocompleteInput: "",
+      };
+  }
+
+  return state;
+}
+
+function restoreExpressions() {
+  const exprs = prefs.expressions;
+  if (!exprs.length) {
+    return [];
+  }
+
+  return exprs;
+}
+
+function storeExpressions({ expressions }) {
+  // Return the expressions without the `value` property
+  prefs.expressions = expressions.map(({ input, updating }) => ({
+    input,
+    updating,
+  }));
+}
+
+function appendExpressionToList(state, value) {
+  const newState = { ...state, expressions: [...state.expressions, value] };
+
+  storeExpressions(newState);
+  return newState;
+}
+
+function updateExpressionInList(state, key, value) {
+  const list = [...state.expressions];
+  const index = list.findIndex(e => e.input == key);
+  list[index] = value;
+
+  const newState = { ...state, expressions: list };
+  storeExpressions(newState);
+  return newState;
+}
+
+function deleteExpression(state, input) {
+  const list = [...state.expressions];
+  const index = list.findIndex(e => e.input == input);
+  list.splice(index, 1);
+  const newState = { ...state, expressions: list };
+  storeExpressions(newState);
+  return newState;
+}
+
+export default update;