trxcllnt commented on issue #14973: URL: https://github.com/apache/arrow/issues/14973#issuecomment-1363568418
`toString()` and `toJSON()` are actually really subtle. JS will invoke an instance's `toString()` method when implicitly converting a type to a string representation, and will use `toJSON()` when running through `JSON.stringify()`. I know `toJSON()` sounds like it should return a string, but according to [the docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#description) `toJSON()` should return the value to be serialized, not a string: > If the value has a `toJSON()` method, it's responsible to define what data will be serialized. Instead of the object being serialized, the value returned by the `toJSON()` method when called will be serialized. For example: ```shell # Implicitly converting an Array to a string: > `${[new Date(), 5, {}, {foo:1, bar: 'baz'}]}` 'Thu Dec 22 2022 19:02:07 GMT-0800 (Pacific Standard Time),5,[object Object],[object Object]' # Stringify'ing JSON > JSON.stringify([new Date(), 5, {}, {foo:1, bar: 'baz'}]) '["2022-12-23T03:00:46.440Z",5,{},{"foo":1,"bar":"baz"}]' ``` We can override this via custom `toString()` and `toJSON()` implementations: ```shell > `${[new Date(), 5, {}, {foo:1, bar: 'baz', __proto__: {toString() { return JSON.stringify(this); }}}]}` 'Thu Dec 22 2022 19:00:16 GMT-0800 (Pacific Standard Time),5,[object Object],{"foo":1,"bar":"baz"}' > JSON.stringify([new Date(), 5, {}, {foo:1, bar: 'baz', __proto__: {toJSON() { return {foo: this.foo}; }}}]) '["2022-12-23T03:01:35.003Z",5,{},{"foo":1}]' ``` The implementations we provide in Arrow are intended to follow these semantics. If you want stringified JSON, why not add a `Table.toJSON()` method that returns an Array, then call `JSON.stringify(table.toJSON())`? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
