Introduce shared methods for canAdd / canRemoveModeledMethod

Author: robertbrignull

extensions/ql-vscode/src/model-editor/shared/multiple-modeled-methods.ts

@@ -0,0 +1,20 @@
+import { ModeledMethod } from "../modeled-method";
+
+export function canAddNewModeledMethod(
+  modeledMethods: ModeledMethod[],
+): boolean {
+  // Disallow adding methods when there are no modeled methods or where there is a single unmodeled method.
+  // In both of these cases the UI will already be showing the user inputs they can use for modeling.
+  return (
+    modeledMethods.length > 1 ||
+    (modeledMethods.length === 1 && modeledMethods[0].type !== "none")
+  );
+}
+
+export function canRemoveModeledMethod(
+  modeledMethods: ModeledMethod[],
+): boolean {
+  // Don't allow removing the last modeled method. In this case the user is intended to
+  // set the type to "none" instead.
+  return modeledMethods.length > 1;
+}

extensions/ql-vscode/src/view/method-modeling/MultipleModeledMethodsPanel.tsx

@@ -2,6 +2,10 @@ import * as React from "react";
 import { useCallback, useMemo, useState } from "react";
 import { Method } from "../../model-editor/method";
 import { ModeledMethod } from "../../model-editor/modeled-method";
+import {
+  canAddNewModeledMethod,
+  canRemoveModeledMethod,
+} from "../../model-editor/shared/multiple-modeled-methods";
 import { styled } from "styled-components";
 import { MethodModelingInputs } from "./MethodModelingInputs";
 import { VSCodeButton } from "@vscode/webview-ui-toolkit/react";
@@ -171,18 +175,15 @@ export const MultipleModeledMethodsPanel = ({
             appearance="icon"
             aria-label="Delete modeling"
             onClick={handleRemoveClick}
-            disabled={modeledMethods.length < 2}
+            disabled={!canRemoveModeledMethod(modeledMethods)}
           >
             <Codicon name="trash" />
           </VSCodeButton>
           <VSCodeButton
             appearance="icon"
             aria-label="Add modeling"
             onClick={handleAddClick}
-            disabled={
-              modeledMethods.length === 0 ||
-              (modeledMethods.length === 1 && modeledMethods[0].type === "none")
-            }
+            disabled={!canAddNewModeledMethod(modeledMethods)}
           >
             <Codicon name="add" />
           </VSCodeButton>