Array of tuples data structure not working when parsing is disabled

[inad9300]

When switching from an array of objects to an array of tuples on a line chart, I get the following TypeScript error:

Type '[number, number]' is not assignable to type 'number | Point | null'.

Furthermore, with parsing set to false, provided I erase type information through casts to any to skip TypeScript's checks, the line stops being drawn on the chart, so I am unable to apply this recommended performance optimization:

Provide prepared data in the internal format accepted by the dataset and scales, and set parsing: false. See Data structures for more information.

Reproducible sample

• TypeScript issue
• Runtime issue

chart.js version

v4.5.1

[blueyedblues]

Gayalea Risley

…

On Wed, Apr 8, 2026, 3:16 AM Daniel M. ***@***.***> wrote: *inad9300* created an issue (chartjs/Chart.js#12232) <#12232> Expected behavior When switching from an array of objects <https://chartjs.org/docs/latest/general/data-structures.html#object> to an array of tuples <https://chartjs.org/docs/latest/general/data-structures.html#array> on a line chart with parsing set to false, I get the following TypeScript error: Type '[number, number]' is not assignable to type 'number | Point | null'. Furthermore, if I erase type information through casts to any to skip TypeScript's checks, the line stops being drawn on the chart. Current behavior https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBAbzgYQBYENYBoUdgEXRnTgF84AzKCEOAcgGM8YA6AKwGc6BuAWACgBDCADsO8ACZF0ALlyYYhYgB46AG2AiApnQB8cALyIBcOFOIctMDnIDaCE6acB6Z2el2kADzkAGHACefmQ43nIAjP5wQXCRZAC6cK5wAOrQANaaAOaOTu7EdrZRvvE4tpE4kfGJyQByEPAA7hnZuQkCpHyC-NqN8rAAFBIQDACuIFoirACOo1pQAQDKWmpaDDDQA4zoIgBu6FwAlACEoY4wAWBacuqaOliO5ugP-KYQYDDAojbGr05gmA42TkFHQaksjlIHUOXSAA Reproducible sample https://codepen.io/inad9300/pen/QwKVvaY?editors=0010 Optional extra steps/info to reproduce *No response* Possible solution *No response* Context *No response* chart.js version v4.5.1 Browser name and version *No response* Link to your project *No response* — Reply to this email directly, view it on GitHub <#12232>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEOYJ6NBB6OVVRAVZRTXDXL4UYRJDAVCNFSM6AAAAACXQYJUX6VHI2DSMVQWIX3LMV43ASLTON2WKOZUGIZDGNZWGA2TENI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[subodhbhyri]

I've looked into this issue. The TypeScript error is caused by [number, number] not being included in the defaultDataPoint union for line and scatter chart types, even though bar charts already support it.
I've opened a PR that adds [number, number] to the defaultDataPoint for both line and scatter in src/types/index.d.ts, along with type test cases to cover the fix.
Note- this PR only addresses the TypeScript type error. The runtime issue (line not being drawn when parsing: false and tuple data is used) is a separate problem in the data parsing pipeline and is not covered by this fix.