Inaccurate type definitions

Oct 13, 2025 by miodeya.com 85 views

Introduction

While working with the restore-state event on the DataTable component in a TypeScript codebase, I encountered an issue where I tried reading from a field on the event object and got a runtime error due to it being undefined. This article aims to highlight the inaccuracies in the DataTableStateEvent type provided by the type definitions and propose a solution to address these issues.

Describe the bug

When working with the DataTable component, I noticed that the restore-state event emits an object that is loaded from storage. However, this object does not contain all the keys at all times, as the component skips saving unnecessary values. This behavior is not accurately reflected in the DataTableStateEvent type, which does not flag fields as optional with ? and does not include | null for fields with default: null in the component code.

Inaccurate type definitions

The DataTableStateEvent type provided by the type definitions has several inaccuracies:

Some fields are typed as | undefined, but none of them are flagged as optional with ?.
Fields with default: null in the component code should be typed as | null.
The selectionKeys field is incorrectly typed as an array, when it's actually a map object.

Reproducer

To reproduce the behavior, follow these steps:

Load the StackBlitz reproduction: https://stackblitz.com/edit/primevue-4-stateful-table-type-issue
Change the state of the two tables and hit the "refresh" button.
Observe the data that is returned from the stateRestore event for each table.

Expected behavior

The returned data would match the shape defined by the DataTableStateEvent type.

Environment

The reproduction was tested on the following environment:

System: macOS 15.3.1
CPU: (8) arm64 Apple M1 Pro
Memory: 89.66 MB / 32.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
- Node: 20.18.0 - ~/.nvm/versions/node/v20.18.0/bin/node
- npm: 10.8.2 - ~/.nvm/versions/node/v20.18.0/bin/npm
- pnpm: 9.15.4 - ~/.nvm/versions/node/v20.18.0/bin/pnpm
Managers:
- Homebrew: 4.4.21 - /opt/homebrew/bin/brew
- pip3: 21.2.4 - /usr/bin/pip3
- RubyGems: 3.0.3.1 - /usr/bin/gem
Utilities:
- Make: 3.81 - /usr/bin/make
- GCC: 16.0.0 - /usr/bin/gcc
- Git: 2.39.5 - /usr/bin/git
- Clang: 16.0.0 - /usr/bin/clang
- Curl: 8.7.1 - /usr/bin/curl
- OpenSSL: 3.3.6 - /usr/bin/openssl
Servers:
- Apache: 2.4.62 - /usr/sbin/apachectl
IDEs:
- Vim: 9.1 - /usr/bin/vim
- Xcode: /undefined - /usr/bin/xcodebuild
Languages:
- Bash: 3.2.57 - /bin/bash
- Perl: 5.34.1 - /usr/bin/perl
- Python3: 3.9.6 - /usr/bin/python3
- Ruby: 2.6.10 - /usr/bin/ruby
Databases:
- SQLite: 3.43.2 - /usr/bin/sqlite3
Browsers:
- Chrome: 134.0.6998.88
- Safari: 18.3

Vue version

3.5.13

PrimeVue version

4.2.5

Node version

20.18.0

Browser(s)

No response.

Conclusion

The DataTableStateEvent type provided by the type definitions does not accurately reflect the behavior of the DataTable component. This article highlights the inaccuracies in the type definitions and proposes a solution to address these issues. By updating the type definitions to reflect the actual behavior of the component, developers can avoid runtime errors and ensure that their code is more robust and maintainable.

Proposed solution

To address the inaccuracies in the DataTableStateEvent type, the following changes can be made:

Flag fields as optional with ? where necessary.
Include | null for fields with default: null in the component code.
Update the type of the selectionKeys field to a map object.

By implementing these changes, the DataTableStateEvent type will accurately reflect the behavior of the DataTable component, and developers can write more robust and maintainable code.

Future work

To further improve the accuracy of the DataTableStateEvent type, the following steps can be taken:

Review the component code to ensure that all fields are properly typed.
Update the type definitions to reflect any changes made to the component code.
Test the updated type definitions to ensure that they accurately reflect the behavior of the component.

Q: What is the issue with the DataTableStateEvent type?

A: The DataTableStateEvent type provided by the type definitions does not accurately reflect the behavior of the DataTable component. Specifically, it does not flag fields as optional with ? and does not include | null for fields with default: null in the component code.

Q: What are the consequences of this inaccuracy?

A: The inaccuracy in the DataTableStateEvent type can lead to runtime errors when trying to access fields that are not present in the event object. This can make it difficult to write robust and maintainable code.

Q: How can I reproduce the issue?

A: To reproduce the issue, follow these steps:

Load the StackBlitz reproduction: https://stackblitz.com/edit/primevue-4-stateful-table-type-issue
Change the state of the two tables and hit the "refresh" button.
Observe the data that is returned from the stateRestore event for each table.

Q: What is the expected behavior?

A: The returned data would match the shape defined by the DataTableStateEvent type.

Q: What is the environment in which the issue was tested?

A: The issue was tested on the following environment:

System: macOS 15.3.1
CPU: (8) arm64 Apple M1 Pro
Memory: 89.66 MB / 32.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
- Node: 20.18.0 - ~/.nvm/versions/node/v20.18.0/bin/node
- npm: 10.8.2 - ~/.nvm/versions/node/v20.18.0/bin/npm
- pnpm: 9.15.4 - ~/.nvm/versions/node/v20.18.0/bin/pnpm
Managers:
- Homebrew: 4.4.21 - /opt/homebrew/bin/brew
- pip3: 21.2.4 - /usr/bin/pip3
- RubyGems: 3.0.3.1 - /usr/bin/gem
Utilities:
- Make: 3.81 - /usr/bin/make
- GCC: 16.0.0 - /usr/bin/gcc
- Git: 2.39.5 - /usr/bin/git
- Clang: 16.0.0 - /usr/bin/clang
- Curl: 8.7.1 - /usr/bin/curl
- OpenSSL: 3.3.6 - /usr/bin/openssl
Servers:
- Apache: 2.4.62 - /usr/sbin/apachectl
IDEs:
- Vim: 9.1 - /usr/bin/vim
- Xcode: /undefined - /usr/bin/xcodebuild
Languages:
- Bash: 3.2.57 - /bin/bash
- Perl: 5.34.1 - /usr/bin/perl
- Python3: 3.9.6 - /usr/bin/python3
- Ruby: 2.6.10 - /usr/bin/ruby
Databases:
- SQLite: 3.43.2 - /usr/bin/sqlite3
Browsers:
- Chrome: 134.0.6998.88
- Safari: 18.3

Q: What are the Vue and PrimeVue versions used in the reproduction?

A: The reproduction was tested on the following versions:

Vue: 3.5.13
PrimeVue: 4.2.5

Q: What is the Node version used in the reproduction?

A: The reproduction was tested on Node version 20.18.0.

Q: What are the steps to reproduce the issue?

A: To reproduce the issue, follow these steps:

Load the StackBlitz reproduction: https://stackblitz.com/edit/primevue-4-stateful-table-type-issue
Change the state of the two tables and hit the "refresh" button.
Observe the data that is returned from the stateRestore event for each table.

Q: What is the expected outcome?

A: The returned data would match the shape defined by the DataTableStateEvent type.

Q: How can I contribute to the solution?

A: If you are interested in contributing to the solution, please review the component code to ensure that all fields are properly typed. Update the type definitions to reflect any changes made to the component code. Test the updated type definitions to ensure that they accurately reflect the behavior of the component.