js-doc / google-closure-compiler how to document passed enum object itself? - javascript

e.g.
/**
* Super my enum
* #enum {number}
*/
var MyEnum = {
ONE: 1,
TWO: 2
};
/**
* #param {what type is it?} enumObj
*/
function showEnum(enumObj) {
console.log(enumObj);
}
//show the enum definition object
showEnum(MyEnum);
how to describe parameter type as not the value/instance of MyEnum, but as the MyEnum object itself?

Use !MyEnum where the ! means "non-null".
/**
* #param {!MyEnum} enumObj
*/
function showEnum(enumObj) {
console.log(enumObj);
}

the solution i tested in WebStorm and VSCode for autocompletion is to use typeof MyEnum.
Its still invalid JSDoc, but supported for autocompletion by IDEs.
/**
* #param {typeof MyEnum} enumObj
*/
function showEnum(enumObj) {
console.log(enumObj);
}

Related

Type information for a conditional property in JSDoc

I'm adding type information for TypeScript to an existing JavaScript library via JSDoc. I have a constructor function that might set a property based on the value(s) of the parameter(s) it's given:
/**
* Settings you can use to configure an instance of an {#link ExampleClass}
*
* #typedef {Object} ExampleOptions
* #property {true} [option] You can set this to `true` to make a property on an instance of {#link ExampleClass} exist. If you don't set it, that property won't exist
*/
/**
* A thing that does stuff
*
* #constructor
* #param {ExampleOptions} [param] Options you can use to configure the new instance
*/
function ExampleClass(param) {
if(param.option === true) {
/**
* A property that only exists based on the options given to this constructor
*
* #type {boolean}
*/
this.property = true;
}
}
I was hoping that TypeScript would externally interpret the declaration of property to be like property?: boolean;, but it looks like it gets interpreted to be non-optional, and comes up in the autocomplete in my editor without having to check for its existence ahead of time. Ideally, I'd like for it to be an optional property that you'd have to check for before you can use it, or even allow you to use it unchecked if TypeScript can somehow guarantee that you had passed {option: true} to the constructor. How can I make that work?
Pre-declare the class with a #typedef with the optional properties and set it to the constructor as a variable of type {new () => ExampleClass}. This way it's even possible to declare this as the defined class and have code completion inside the constructor function itself. Something like the below:
/**
* Settings you can use to configure an instance of an {#link ExampleClass}
*
* #typedef {Object} ExampleOptions
* #property {true} [option] You can set this to `true` to make a property on an instance of {#link ExampleClass} exist. If you don't set it, that property won't exist
*/
/**
* #typedef {object} ExampleClass
* #prop {boolean} [property] A property that only exists based on the options given to this constructor
*/
/**
* A thing that does stuff
*
* #constructor
* #param {ExampleOptions} [param] Options you can use to configure the new instance
* #this {ExampleClass}
* #type {{new () => ExampleClass}}
*/
const ExampleClass = function (param) {
if(param.option === true) {
this.property = true;
}
}
Can you not just do
interface options {
option? : boolean;
}
/**
* A thing that does stuff
*
* #constructor
* #param {options} [param] Options you can use to configure the new instance
*/
function ExampleClass(param : options) {
if(param.option === true) {
/**
* A property that only exists based on the options given to this constructor
*
* #type {boolean}
*/
this.property = true;
}
}

JSDoc, treat POJO as instance of Class

I have a class and a function that takes instance of that class or a similar POJO object as argument.
I want to annotate this function using JSDoc.
class Test {
constructor(a, b) {
this.a = a;
this.b = b;
}
}
/**
* #param {Test} test
*/
function handleTest(test) {
console.log(test.a, test.b);
}
// Webstorm complains that argument is not of type Test
handleTest({
a: 'this is a'
});
Using #param {Test} test almost works... but WebStorm complains that POJO isn't assignable to type Test.
Is there some JSDoc trick I can do to make it clear that both instance of Test and a Test-like object are both OK?
Use type union:
/**
* #param {Test|{a,b}} test
*/
function handleTest(test) {
console.log(test.a, test.b);
}
The |{a,b} part of the type denotes separate allowable types. You could just use {Test|{}} but then the IDE doesn't know that a and b are expected properties.
That's the shorthand version; you could also define what "Test-like" objects are in case you plan on using and documenting TestLike objects in more than one place:
/**
* #typedef {object} TestLike
* #property {string} a - some property a
* #property {string} b - some property b
*/
/**
* #param {Test|TestLike} test
*/
handleTest(test) {
// ...
}

JSDoc: Annotating an exported method

If I define an object like this:
/**
* My Cool Object
* #constructor
*/
function MyCoolObject() {
/**
* Cool Method, private
* #param {!string} parameter
*/
function localMethod(parameter) {
// do stuff
}
// Export the method
this.exportedMethod = localMethod;
}
I'd like to know, if at all possible, how to tell JSDOC to use the annotation for localMethod in exportedMethod, or how can I annotate exportedMethod, because if I do:
// Export the method
/**
* Cool Method
* #param {!string} parameter
*/
this.exportedMethod = localMethod;
JSDOC assumes it's a field rather than a method, then only uses the description, ignoring the #param part.
I would reduce it to:
/**
* My Cool Object
* #constructor
*/
function MyCoolObject() {
/**
* Cool Method, private
* #param {!string} parameter
*/
this.exportedMethod = function (parameter) {
// do stuff
};
}
You can do var localMethod = this.exportedMethod right after if you want a local reference to the method. In the off chance that you've over-simplified your example and you need to first assign to localMethod before assigning to this.exportedMethod you could do this:
/**
* My Cool Object
* #constructor
*/
function MyCoolObject() {
function localMethod(parameter) {
// do stuff
}
/**
* Cool Method, private
* #param {!string} parameter
* #function
*/
// Export the method
this.exportedMethod = localMethod;
}
The #function declaration tells jsdoc that it is dealing with a function.

Closure-compiler param type Object.<string, *> doesn't works as expected

What would be the correct way to annotate the types of options that I could pass through an object as a function argument? Example:
/**
* test() function can receive all type of options.
* #param {Object.<string, *>} options
* #expose
*/
function test(options) {
if(typeof options.set !== "undefined") {
alert(options.set);
}
if(typeof options.callback !== "undefined") {
options.callback.apply(this, []);
}
}
How I can define something like it ... ?
/**
* #param {Object.<string, *>} options
* #param {Object.<string, *>} options.set
* #param {function(... [*])} options.callback
*/
If I not does nothing, the compiler return an error like:
script.js:28: WARNING - Property callback never defined on Object.<string, *>
options.callback.apply(this, []);
^
Usage method:
java -jar "compiler.jar"
--compilation_level ADVANCED_OPTIMIZATIONS
--warning_level VERBOSE
--js "script.js"
--js_output_file "script.min.js"
You could use the record type:
#param {{set: Object, callback: function}} options
If you want to specify each option exactly you can do it like this:
/**
* #param {{row: number, field: string, callback: function(string) }} options
*/
So you can declare object structure, including types, details are here.
Just need to create a new variable and set it as a #constructor, #exposeing all this methods, like:
/**
* #constructor
*/
var TestOptions = function() {
/**
* #type {Object.<string, *>}
* #expose
*/
this.set;
/**
* #type {function(... [*])}
* #expose
*/
this.callback;
};
After I just need set this as #param type, like:
/**
* test() function can receive all type of options.
* #param {TestOptions} options
* #expose
*/
function test(options) {
/* ... */
}
TestOptions will not be on script.min.js because I never used new on it.

Properly type instance variables with closure compiler

I cannot get to properly type the following piece of code:
/**
* #constructor
*/
function F() {
this.a = 0;
};
/**
* #type {function(number)}
*/
F.prototype.g = function(b) {
this.a += b;
};
I get the following warning:
test.js:12: WARNING - could not determine the type of this expression
this.a += b;
^
How can I properly type this in this example?
-- EDIT --
If you want to see the warning, you need to set reportUnknownTypes to trueas explained here. I am trying to get to 100% typed code and I figured I could not reach that for that simple a program.
/** #type {function(number)} */
doesn't specify the "this" type so it is unknown. To specify it in that fashion you would want to use:
/** #type {function(this:F, number)}
Using "#param {number}" lets the compiler infer the "this" type from the fact it was declared on F's prototype.
You seem to need to use #param {number} b instead of #type {function(number)}. Typing with #param doesn't throw the warning. Doesn't make a whole lot of sense, but it works:
/**
* #param {number} b
*/
F.prototype.g = function(b) {
this.a += b;
};
--
Original answer:
I think it's because you didn't type a in your constructor. Try this:
/**
* #constructor
*/
function F() {
/**
* #type {number}
* #private
*/
this.a = 0;
};

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