CSF tools: Support Template.bind() substitution

lib/csf-tools/src/CsfFile.test.ts

@@ -158,7 +158,7 @@ describe('csf extract', () => {
           - id: foo-bar--a
             name: A
             parameters:
-              __isArgsStory: false
+              __isArgsStory: true
               __id: foo-bar--a
       `);
     });

lib/csf-tools/src/CsfFile.ts

@@ -55,6 +55,63 @@ const parseMeta = (declaration: t.ObjectExpression): Meta => {
   });
   return meta;
 };
+
+const findVarInitialization = (identifier: string, program: t.Program) => {
+  let init: t.Node = null;
+  let declarations: t.VariableDeclarator[] = null;
+  program.body.find((node: t.Node) => {
+    if (t.isVariableDeclaration(node)) {
+      declarations = node.declarations;
+    } else if (t.isExportNamedDeclaration(node) && t.isVariableDeclaration(node.declaration)) {
+      declarations = node.declaration.declarations;
+    }
+
+    return (
+      declarations &&
+      declarations.find((decl: t.Node) => {
+        if (
+          t.isVariableDeclarator(decl) &&
+          t.isIdentifier(decl.id) &&
+          decl.id.name === identifier
+        ) {
+          init = decl.init;
+          return true; // stop looking
+        }
+        return false;
+      })
+    );
+  });
+  return init;
+};
+
+const isArgsStory = ({ init }: t.VariableDeclarator, parent: t.Node) => {
+  let storyFn: t.Node = init;
+  // export const Foo = Bar.bind({})
+  if (t.isCallExpression(init)) {
+    const { callee, arguments: bindArguments } = init;
+    if (
+      t.isProgram(parent) &&
+      t.isMemberExpression(callee) &&
+      t.isIdentifier(callee.object) &&
+      t.isIdentifier(callee.property) &&
+      callee.property.name === 'bind' &&
+      (bindArguments.length === 0 ||
+        (bindArguments.length === 1 &&
+          t.isObjectExpression(bindArguments[0]) &&
+          bindArguments[0].properties.length === 0))
+    ) {
+      const boundIdentifier = callee.object.name;
+      const template = findVarInitialization(boundIdentifier, parent);
+      if (template) {
+        storyFn = template;
+      }
+    }
+  }
+  if (t.isArrowFunctionExpression(storyFn)) {
+    return storyFn.params.length > 0;
+  }
+  return false;
+};
 export class CsfFile {
   _ast: Node;
 
@@ -85,7 +142,7 @@ export class CsfFile {
         },
       },
       ExportNamedDeclaration: {
-        enter({ node }) {
+        enter({ node, parent }) {
           if (t.isVariableDeclaration(node.declaration)) {
             // export const X = ...;
             node.declaration.declarations.forEach((decl) => {
@@ -94,8 +151,7 @@ export class CsfFile {
                 const parameters = {
                   // __id: toId(self._meta.title, name),
                   // FiXME: Template.bind({});
-                  __isArgsStory:
-                    t.isArrowFunctionExpression(decl.init) && decl.init.params.length > 0,
+                  __isArgsStory: isArgsStory(decl, parent),
                 };
                 self._stories[name] = {
                   id: 'FIXME',