14 optional default function parameters in typescript

okay, let's dive deep into optional default function parameters in typescript. this is a powerful feature that allows you to create more flexible and maintainable functions, handling cases where the caller doesn't always need to provide every argument.

**understanding optional and default parameters**

* **optional parameters:** these parameters are marked with a `?` after the parameter name in the function signature. the function can be called without providing a value for them. if a value isn't provided, the parameter's value inside the function will be `undefined`.

* **default parameters:** these parameters have a default value assigned to them in the function signature. if the function is called without providing a value for the parameter, the default value will be used.

typescript allows you to combine both optional and default parameters, adding even more flexibility.

**key rules and considerations**

1. **placement:** optional parameters *must* come after required parameters. default parameters are similar, but with a subtle nuance. parameters with default values can be positioned before required parameters as long as the caller calls the function with `undefined` to use the default value. if there is a required parameter before a default parameter, it will be assigned that default parameter.

2. **type inference:** typescript can often infer the type of a default parameter based on the default value. however, it's good practice to explicitly specify the type for clarity and prevent unexpected behavior.

3. **optional vs. default:**
* use optional parameters when the absence of a value is a valid case that your function needs to handle (often checking if the value is `undefined`).
* use default parameters when you want a sensible fallback value if the caller doesn't provide one.

4. **"rest" parameters (variable arguments):** while not directly part of optional/default parameters, they often work together to allow functions to acc ...

#TypeScript #OptionalParameters #DefaultFunctions

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