Linqu to JavaScript

1. Select

• LINQ: .Select(x => x * 2)
• JavaScript: .map(x => x * 2)

2. Where

• LINQ: .Where(x => x > 10)
• JavaScript: .filter(x => x > 10)

3. First

• LINQ: .First()
• JavaScript: [0] (for first item) or .find(() => true) (for first that matches a condition)

4. FirstOrDefault

• LINQ: .FirstOrDefault()
• JavaScript: .find(() => true) || defaultValue

5. Last

• LINQ: .Last()
• JavaScript: [array.length - 1] or .slice(-1)[0]

6. LastOrDefault

• LINQ: .LastOrDefault()
• JavaScript: .slice(-1)[0] || defaultValue

7. SelectMany

• LINQ: .SelectMany(x => x.Items)
• JavaScript: .flatMap(x => x.Items)

8. OrderBy

• LINQ: .OrderBy(x => x.Prop)
• JavaScript: .sort((a, b) => a.Prop - b.Prop) (for ascending order)

9. OrderByDescending

• LINQ: .OrderByDescending(x => x.Prop)
• JavaScript: .sort((a, b) => b.Prop - a.Prop) (for descending order)

10. All

• LINQ: .All(x => x > 10)
• JavaScript: .every(x => x > 10)

11. Any

• LINQ: .Any(x => x > 10)
• JavaScript: .some(x => x > 10)

12. Count

• LINQ: .Count(x => x > 10)
• JavaScript: .filter(x => x > 10).length

13. Sum

• LINQ: .Sum(x => x.Prop)
• JavaScript: .reduce((acc, x) => acc + x.Prop, 0)

14. Max

• LINQ: .Max(x => x.Prop)
• JavaScript: .reduce((max, x) => x.Prop > max ? x.Prop : max, -Infinity)

15. Min

• LINQ: .Min(x => x.Prop)
• JavaScript: .reduce((min, x) => x.Prop < min ? x.Prop : min, Infinity)

16. Distinct

• LINQ: .Distinct()
• JavaScript: [...new Set(array)]

17. GroupBy

• LINQ: .GroupBy(x => x.Prop)
• JavaScript:

  array.reduce((grouped, x) => {
    const key = x.Prop;
    if (!grouped[key]) grouped[key] = [];
    grouped[key].push(x);
    return grouped;
  }, {});
  

18. Aggregate

• LINQ: .Aggregate((acc, x) => acc + x.Prop)
• JavaScript: .reduce((acc, x) => acc + x.Prop)

19. Take

• LINQ: .Take(3)
• JavaScript: .slice(0, 3)

20. Skip

• LINQ: .Skip(3)
• JavaScript: .slice(3)