This repo illustrates what I consider a bug in the typescript code generator for the useDefineForClassFields
feature.
This has been tested in Node v18.
Run npm run test:node
to execute the plain node script.
➜ ts-define-class-field-bug git:(main) npm run test:node
> [email protected] test:node
> node test-node.js
/Users/jan/development/ts-define-class-field-bug/test-node.js:3
throw new Error()
^
Error
at A.foo (/Users/jan/development/ts-define-class-field-bug/test-node.js:3:11)
at Object.<anonymous> (/Users/jan/development/ts-define-class-field-bug/test-node.js:10:3)
at Module._compile (node:internal/modules/cjs/loader:1149:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1203:10)
at Module.load (node:internal/modules/cjs/loader:1027:32)
at Module._load (node:internal/modules/cjs/loader:868:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
at node:internal/main/run_main_module:23:47
Node.js v18.10.0
Observe that the name of the method that errored is reported as A.foo
Run npm run test:useDefine
to execute the Typescript version with the useDefineForClassFields
flag
➜ ts-define-class-field-bug git:(main) ✗ npm run test:useDefine
> [email protected] test:useDefine
> tsc --useDefineForClassFields && node test-typescript.js
/Users/jan/development/ts-define-class-field-bug/test-typescript.js:9
throw new Error();
^
Error
at A.value (/Users/jan/development/ts-define-class-field-bug/test-typescript.js:9:23)
at Object.<anonymous> (/Users/jan/development/ts-define-class-field-bug/test-typescript.js:22:3)
at Module._compile (node:internal/modules/cjs/loader:1149:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1203:10)
at Module.load (node:internal/modules/cjs/loader:1027:32)
at Module._load (node:internal/modules/cjs/loader:868:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
at node:internal/main/run_main_module:23:47
Node.js v18.10.0
Observe that the name of the method that errored is reported as A.value
.
The function object that Javascript creates gets the name of its value
key in the property descriptor of defineProperty
.
This problem becomes quite annoying when used in the common pattern of pre-binding arrow-functions to class instances,
and then passing them around as event handlers in the browser.
Stack traces and the Chromium flame graph are then full of methods named value
.