various-ways-to-invoke-functions-in-dart

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There are multiple ways to call a Function in Dart.

The examples below will assume the following function:

void myFunction(int a, int b, {int? c, int? d}) {
  print((a, b, c, d));
}

But recently I learned that you can call a functions positional arguments in any order mixed with the named arguments. 🤯

myFunction(1, 2, c: 3, d: 4);
myFunction(1, c: 3, d: 4, 2);
myFunction(c: 3, d: 4, 1, 2);
myFunction(c: 3, 1, 2, d: 4);

In addition you can use the

.call

operator to invoke the function if you have a reference to it:

myFunction.call(1, 2, c: 3, d: 4);

You can also use

Function.apply

to dynamically invoke a function with a reference but it should be noted that it will effect js dart complication size and performance:

Function.apply(myFunction, [1, 2], {#c: 3, #d: 4});

All of these methods print the following:

(1, 2, 3, 4)

在Dart中，调用Function有多种方式。

以下示例将基于如下函数展开：

void myFunction(int a, int b, {int? c, int? d}) {
  print((a, b, c, d));
}

不过我最近发现，调用函数时可以将位置参数与命名参数以任意顺序混合使用。 🤯

myFunction(1, 2, c: 3, d: 4);
myFunction(1, c: 3, d: 4, 2);
myFunction(c: 3, d: 4, 1, 2);
myFunction(c: 3, 1, 2, d: 4);

此外，如果你持有函数的引用，还可以使用

.call

运算符来调用它：

myFunction.call(1, 2, c: 3, d: 4);

你也可以使用

Function.apply

通过引用来动态调用函数，但需要注意的是，这会影响Dart转JS后的代码体积和性能：

Function.apply(myFunction, [1, 2], {#c: 3, #d: 4});

所有这些方法都会输出以下内容：

(1, 2, 3, 4)