fix if statement and support context module

Author: baseballyama

src/rules/valid-context-access.ts

@@ -8,7 +8,6 @@ export default createRule("valid-context-access", {
       description:
         "context functions must be called during component initialization.",
       category: "Possible Errors",
-      // TODO Switch to recommended in the major version.
       recommended: false,
     },
     schema: [],
@@ -19,7 +18,28 @@ export default createRule("valid-context-access", {
     type: "problem",
   },
   create(context) {
-    const scopeManager = context.getSourceCode().scopeManager
+    // // This rule doesn't check other than Svelte files.
+    if (!context.parserServices.isSvelte) {
+      return {}
+    }
+
+    // Extract <script> blocks that is not module=context.
+    const sourceCode = context.getSourceCode()
+    const scriptNotModuleElements = sourceCode.ast.body.filter((b) => {
+      if (b.type !== "SvelteScriptElement") return false
+      const isModule = b.startTag.attributes.some((a) => {
+        return (
+          a.type === "SvelteAttribute" &&
+          a.key.name === "context" &&
+          a.value.some(
+            (v) => v.type === "SvelteLiteral" && v.value === "module",
+          )
+        )
+      })
+      return !isModule
+    })
+
+    const scopeManager = sourceCode.scopeManager
     const toplevelScope =
       scopeManager.globalScope?.childScopes.find(
         (scope) => scope.type === "module",
@@ -53,17 +73,32 @@ export default createRule("valid-context-access", {
       return []
     }
 
+    /** Return true if the node is there inside of <script> block that is not module=context. */
+    function isInsideOfSvelteScriptElement(node: TSESTree.Node) {
+      for (const script of scriptNotModuleElements) {
+        if (
+          node.range[0] >= script.range[0] &&
+          node.range[1] <= script.range[1]
+        ) {
+          return true
+        }
+      }
+      return false
+    }
+
     /** Let's lint! */
     function doLint(
       visitedCallExpressions: TSESTree.CallExpression[],
       contextCallExpression: TSESTree.CallExpression,
       currentNode: TSESTree.CallExpression,
     ) {
-      let { parent } = currentNode
-      if (parent?.type !== "ExpressionStatement") {
+      // Report if context function is called outside of <script> block.
+      if (!isInsideOfSvelteScriptElement(currentNode)) {
         report(contextCallExpression)
         return
       }
+
+      let { parent } = currentNode
       while (parent) {
         parent = parent.parent
         if (

tests/fixtures/rules/valid-context-access/invalid/case03-input.svelte

@@ -3,8 +3,6 @@
   const something = () => {
     setContext("answer", 42)
   }
-
-  something()
 </script>
 
 <button on:click={() => something()}>Click Me</button>

tests/fixtures/rules/valid-context-access/invalid/case08-errors.yaml

@@ -0,0 +1,3 @@
+- message: Do not call setContext except during component initialization.
+  line: 3
+  column: 3

tests/fixtures/rules/valid-context-access/invalid/case08-input.svelte

@@ -0,0 +1,4 @@
+<script context="module">
+  import { setContext } from "svelte"
+  setContext("answer", 42)
+</script>

tests/fixtures/rules/valid-context-access/valid/case03-input.svelte

@@ -1,5 +1,5 @@
 <script>
-  import { setContext, onMount } from "svelte"
+  import { setContext } from "svelte"
   const something = () => {
     setContext("answer", 42)
   }

tests/fixtures/rules/valid-context-access/valid/case08-input.svelte

@@ -0,0 +1,22 @@
+<script>
+  import { setContext, onMount } from "svelte"
+
+  if (setContext("answer", 42)) {
+    console.log("setContext")
+  } else if (setContext("answer", 43)) {
+    console.log("setContext")
+  }
+
+  switch (setContext("answer", 42)) {
+    case 1:
+      console.log("setContext")
+      break
+    case 2:
+      console.log("setContext")
+      break
+    default:
+      console.log("setContext")
+  }
+
+  const foo = setContext("answer", 42) ? "bar" : "baz"
+</script>

tests/fixtures/rules/valid-context-access/valid/case09-input.js

@@ -0,0 +1,17 @@
+import { setContext } from "svelte"
+
+const something = () => {
+  setContext("answer", 42)
+}
+
+const something2 = async () => {
+  await Promise.resolve()
+  setContext("answer", 42)
+}
+
+const aaa = (fn) => {
+  fn()
+}
+
+aaa(() => something())
+something2()