tslint不会在* .js文件中检测到未声明的变量

Question

Under Visual Code and using tslint to also check *.ts and *.js files, undeclared variable are not detected in .js files as they are in .ts files.

Any idea ?

As you can see no-console is well detected on both files : .js and .ts iterableGGG is not declared => in the ts file, it is underlined in red. But not in the js file.

Note: the import from lodash is just there to have a module, so variables in the ts file are not global.

tslint.json

{
    "defaultSeverity": "error",
    "extends": [
        "tslint:recommended"
    ],
    "jsRules": {},
    "rules": {
        "no-any": false
    },
    "rulesDirectory": []
}

Answer 1

I believe that the jsRules should look like the following if I'm not mistaken.

"jsRules": {
    "no-use-before-declare": true
}

Answer 2

I found the solution.

in the TS file the undeclared variable iterableGGG is detected by tsc NOT tslint, You can observe that because in VC the warning/error popup message begins with [ts] instead of [tslint] . And when tslint detect sth, there is a rule name (for ex : "no-use-before-declare") You also see that in CLI, directly executing the command tsc and tslint. you can check that this type of error is raised by tsc.

>tsc
src/examplJS.js(3,19): error TS2552: Cannot find name 'iterableGGG'. Did you mean 'iterable' ?
src/examplTS.js(5,19): error TS2304: Cannot find name 'iterableGGG'.

so going to the tsc config tsconfig.json, just activate "checkJs" to true and VC will also show the error for JS codes as well as TS

"allowJs": true, /* Allow javascript files to be compiled. */

"checkJs": true, /* Report errors in .js files. */