Build error / TypeError: [vite-plugin-svelte-module] Cannot read properties of undefined (reading 'some')

[imprest]

Describe the bug

I was trying to integrate svelte with phoenix liveview and initially there were no issues.
However after upgrading from [email protected] -> [email protected]. I get the below error when trying to build.
Downgrading to [email protected] successfully builds.

Reproduction

import Counter from "./pages/Counter.svelte";
import Ledgers from "./pages/Ledgers.svelte";

import { mount, unmount } from "svelte";

const components = {
  Counter, Ledgers
};

function parsedProps(el) {
  const props = el.getAttribute("data-props");
  return props ? JSON.parse(props) : {};
}

const Hooks = {};
Hooks.SvelteHook = {
  mounted() {
    const componentName = this.el.getAttribute("data-name");
    if (!componentName) throw new Error("Component name must be provided");

    const requiredApp = components[componentName];
    if (!requiredApp) {
      throw new Error(
        `Unable to find ${componentName} component. Did you forget to import it into hooks.js?`,
      );
    }

    const pushEvent = (event, data, callback) => {
      this.pushEvent(event, data, callback);
    };

    const handleEvent = (event, callback) => {
      this.handleEvent(event, callback);
    }

    const goto = (href) => {
      this.pushHistoryPatch(href, "push", this.el);
    };

    // eslint-disable-next-line no-undef
    const props = $state({ ...parsedProps(this.el), pushEvent, handleEvent, goto })

    this._instance = mount(requiredApp, {
      target: this.el,
      props
    });
  },

  updated() {
    this._instance.update({ ...parsedProps(this.el) })
  },

  destroyed() {
    if (this._instance) {
      window.addEventListener("phx:page-loading-stop", () => unmount(this._instance), { once: true })
    }
  },
};

export default Hooks;

Logs

error during build:
[vite-plugin-svelte-module] [plugin vite-plugin-svelte-module] Cannot read properties of undefined (reading 'some')
file: /home/hvaria/repos/subledger/assets/src/hooks.svelte.js
TypeError: [plugin vite-plugin-svelte-module] Cannot read properties of undefined (reading 'some')
    at validate_assignment (file:///home/hvaria/repos/subledger/assets/node_modules/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js:45:24)
    at AssignmentExpression (file:///home/hvaria/repos/subledger/assets/node_modules/svelte/src/compiler/phases/2-analyze/visitors/AssignmentExpression.js:11:2)
    at next (file:///home/hvaria/repos/subledger/assets/node_modules/zimmerframe/src/walk.js:107:21)
    at _ (file:///home/hvaria/repos/subledger/assets/node_modules/svelte/src/compiler/phases/2-analyze/index.js:126:3)
    at visit (file:///home/hvaria/repos/subledger/assets/node_modules/zimmerframe/src/walk.js:101:13)
    at Object.next (file:///home/hvaria/repos/subledger/assets/node_modules/zimmerframe/src/walk.js:63:23)
    at ExpressionStatement (file:///home/hvaria/repos/subledger/assets/node_modules/svelte/src/compiler/phases/2-analyze/visitors/ExpressionStatement.js:37:10)
    at next (file:///home/hvaria/repos/subledger/assets/node_modules/zimmerframe/src/walk.js:107:21)
    at _ (file:///home/hvaria/repos/subledger/assets/node_modules/svelte/src/compiler/phases/2-analyze/index.js:126:3)
    at visit (file:///home/hvaria/repos/subledger/assets/node_modules/zimmerframe/src/walk.js:101:13)

System Info

upgrade from [email protected] -> [email protected]

Severity

blocking an upgrade

[voscausa]

Same here

[webJose]

Adding me here to add some weight. My package for single-spa is affected, as seen in the report linked above.

[brunocalou]

Same here, but on a SvelteKit project

[dummdidumm]

Please someone provide a proper reproduction so we can reproduce this.

[imprest]

Created a repo to recreate the issue. https://github.com/imprest/serr

[webJose]

@dummdidumm , could the unit tests for my project serve as repro?

1. Clone https://github.com/WJSoftware/wjfe-single-spa-svelte.
2. Run npm ci.
3. Run npm up since there are many outdated packages. This will bring svelte v5.20.0 to the table.
4. Run npm run test. Unit tests should fail.
5. Run npm i [email protected].
6. Run npm run test. Unit tests should succeed.

[tomoam]

Assignments to this.property in a .svelte.js file seem to cause this issue.

It occurs in 5.19.10 and 5.20.0, but with slightly different messages.

• https://svelte.dev/playground/5628d4f8a96d4a32aa19631e82e009fd?version=5.19.10
  • error: Cannot read properties of undefined (reading 'includes')
• https://svelte.dev/playground/5628d4f8a96d4a32aa19631e82e009fd?version=5.20.0
  • error: Cannot read properties of undefined (reading 'some')

It may be due to this change.
https://github.com/sveltejs/svelte/pull/15276/files#diff-650c22803364b65b1d9aa3e102da4dba7e960b0808a9f0d66c199f408a0f1ab7L46-R53

[edeleastar]

Hi @dummdidumm

Same here on this project: tutors

To reproduce on build:

• git clone https://github.com/tutors-sdk/tutors-b.git
• npm install
• npm run build

This builds successfully, using svelte 5.19.3 - with some warnings.

To produce build error,

• npm i [email protected]
• npm install
• npm run build

[vite-plugin-svelte-module] [plugin vite-plugin-svelte-module] Cannot read properties of undefined (reading 'some')"
t validate_assignment (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js:45:24)
    at AssignmentExpression (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/svelte/src/compiler/phases/2-analyze/visitors/AssignmentExpression.js:11:2)
    at next (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/zimmerframe/src/walk.js:107:21)
    at _ (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/svelte/src/compiler/phases/2-analyze/index.js:126:3)
    at visit (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/zimmerframe/src/walk.js:101:13)
    at Object.next (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/zimmerframe/src/walk.js:63:23)
    at ExpressionStatement (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/svelte/src/compiler/phases/2-analyze/visitors/ExpressionStatement.js:37:10)
    at next (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/zimmerframe/src/walk.js:107:21)
    at _ (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/svelte/src/compiler/phases/2-analyze/index.js:126:3)
    at visit (file:///Users/edeleastar/repos/tutor-sdk/test/tutors-b/node_modules/zimmerframe/src/walk.js:101:13)

Thanks in advance