RG.Ninja

List of Available Jutsu:

1. Fluent everything

obj.Setup(o => { ... });
obj.SetupAsync(async o => { ... });
obj.Let(o => { ... return something; });
obj.LetAsync(async o => { ... return something; });

Example:

var button = new Button {
  Text = "Click me"
}
.Setup(btn => Grid.SetRow(btn, 1))
.Setup(btn => btn.Click += ClickMe_Clicked);

2. Spread operation in collection initializer

You can 'spread' IEnumerable and Range in collection initializer:

var obj = new Foo { Items = { someEnumerable } };
var obj = new Foo { Items = { 0..n } };

Example:

record Foo {
    public List<int> Items { get; } = new();
}

var items = new[] { 1, 2, 3 };

var foo = new Foo {
    Items = {
        items, // spread array

        4, 5, 6, // add values normally

        from i in items // spread IEnumerable
        let j = 10 - i
        orderby j ascending
        select j,

        10..13 // spread range
    }
};

// foo.Items: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

3. Spread operation in dictionary initializer

var obj = new Foo { Dictionary = { someDictionary } };
var obj = new Foo { Dictionary = { someCollection, item => item.Id } }; // with key selector
var obj = new Foo { Dictionary = { someCollection, item => item.Id, item => item.Text } }; // with key and value selector

Usage:

record Foo {
    public Dictionary<int, string> Items { get; } = new();
}

var items = new Dictionary<int, string> {
    { 1, "Satu" },
    { 2, "Dua" }
};

var values = new[] { "Tiga", "Empat" };

var foo = new Foo {
    Items = {
        { items }, // spread dictionary

        { values, v => v.Length - 1 }, // spread array using keySelector

        { 5, "Lima" } // add entry normally
    }
};

// foo.Items:
// [1] = "Satu"
// [2] = "Dua"
// [3] = "Tiga"
// [4] = "Empat"
// [5] = "Lima"

4. Enumerable Range

Range in foreach:

// 1 to 4
foreach (int i in 1..5) {
}

// 0 to 4
foreach (int i in ..5) {
}

// 0 to length-1
foreach (int i in ..length) {
}

Range in LINQ:

// simple LINQ
from i in ..arr.length
select arr[i]

// complex LINQ: you need to explicitly specify 'int' as range variable type
from int i in ..arr.length
where i % 2 == 0
select arr[i]

5. Zip, Skip, and Take using Range

// i is index of item in list
foreach ((string item, int i) in list.Zip(..)) {
}

// take elements at index 3 and 4
var result = list.Take(3..5);

// take all elements except those at index 3 and 4
var result = list.Skip(3..5);

6. One<T> and Qlosure<T>

Taken from ronnygunawan/one repo. It allows you to use LINQ expression to write JS closure-like or F# pipeline-like expression:

decimal total = from decimal price in 199m
                let tax = price * 0.1m
                let subtotal = price + tax
                let discount = 10m
                select subtotal - discount;