Detecting typescript syntax errors: checking for if statements and calling class methods

Question

Detecting typescript syntax errors: checking for if statements and calling class methods

When I'm debugging, I've noticed that the silly mistakes I make are often the hardest to spot. For example:

if (id = userId) {..}

And in class methods:

let result = myClass.doThis;

Oddly enough, VSCode doesn't catch these errors during compilation. Is there a tool or setting that can alert me to these issues? Finding them manually can be time-consuming and frustrating, as they're not always easy to spot at first glance.

While these statements are valid in TypeScript, other programming languages often highlight assignments within conditionals and method calls as properties to prevent potential errors. It would be helpful to have a similar warning system in place for TypeScript as well.

typescript visual-studio-code tslint typescript-eslint

Answer 1

Answer №1

Building off of the insights shared by @aluan-haddad.

When it comes to avoiding your initial problem (if (id = userId) {...}), ESLint offers a guideline known as the no-cond-assign rule.

Regarding your second concern (let result = myClass.doThis;), pinpointing the most suitable lint rule to address this can be challenging without additional context. In isolation, there isn't anything inherently flawed with that code - you've simply assigned what appears to be a function to a variable.

An approach that could potentially flag this is the unbound-method rule within @typescript-eslint. However, note that this rule may not detect anything if you're utilizing auto-bound arrow-function methods.

If you encounter situations where you are returning values from functions, TypeScript should generally address this for you. One strategy to ensure this is to uphold stringent contracts for your functions through one of these @typescript-eslint rules:

If you're encountering challenges like if (myClass.doThis) {...}, consider exploring suggestions offered in this response:

Answer 2

Building off of the insights shared by @aluan-haddad.

When it comes to avoiding your initial problem (if (id = userId) {...}), ESLint offers a guideline known as the no-cond-assign rule.

Regarding your second concern (let result = myClass.doThis;), pinpointing the most suitable lint rule to address this can be challenging without additional context. In isolation, there isn't anything inherently flawed with that code - you've simply assigned what appears to be a function to a variable.

An approach that could potentially flag this is the unbound-method rule within @typescript-eslint. However, note that this rule may not detect anything if you're utilizing auto-bound arrow-function methods.

If you encounter situations where you are returning values from functions, TypeScript should generally address this for you. One strategy to ensure this is to uphold stringent contracts for your functions through one of these @typescript-eslint rules:

If you're encountering challenges like if (myClass.doThis) {...}, consider exploring suggestions offered in this response:

Detecting typescript syntax errors: checking for if statements and calling class methods

Answer №1

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