Dangerous "name" (and potentially others) global
#18,433 opened on Sep 13, 2017
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Description
TypeScript Version: 2.6.0-dev.20170913
Code
if (name === "asdf") {
console.log("asdf")
}
https://www.typescriptlang.org/play/#src=if (name %3D%3D%3D "asdf") {%0D%0A console.log('hello')%0D%0A}
Expected behavior:
Error out
Actual behavior:
More than once, I had a "local" variable called name, outside a block scope, and it didn't warn me that it's not defined (or used before declaration). even though, in my code, event.name is a string, the global name variable is of type never. it's defined in lib.dom.d.ts, along with other "juicy" global names that will provide some confusion, like length, external, event, closed
one 'fix' (that would be a breaking change) would to make lib.dom-globals.d.ts (the propertiers that are usually accessible through window variable) and make it an opt-in in tsconfig.json compilerOptions.lib array