Let’s say I have the following type:

interface MyType { 
    myProperty: [a: string[], b: string[]] 
}

and now I want to create an array out of that type:

const array1: MyType[] = [
    {myProperty: [["Hello", "World"], []]},
    {myProperty: [["Hello"], []]},
];

If I try to sort that array:

const array2: MyType[] = [
    {myProperty: [["Hello", "World"], []]},
    {myProperty: [["Hello"], []]},
].sort((a,b) => a.myProperty[0].length - b.myProperty[0].length);

I get an error:

Type '{ myProperty: string[][]; }[]' is not assignable to type 'MyType[]'.

I tried various workarounds:

• Array initialization with sort (lambda)

  const array2: MyType[] = [
      {myProperty: [["Hello", "World"], []]},
      {myProperty: [["Hello"], []]},
  ].sort((a,b) => a.myProperty[0].length - b.myProperty[0].length);
  

  Value doesn’t have correct type

• Array initialization with sort (function)

  const array3: MyType[] = [
      {myProperty: [["Hello", "World"], []]},
      {myProperty: [["Hello"], []]},
  ].sort(compareMyType);
  function compareMyType(a: MyType, b: MyType) { 
      return a.myProperty[0].length - b.myProperty[0].length; 
  }
  

  Sort function doesn’t have correct type and value doesn’t have correct type

• Casting to MyType[]:

  const array4: MyType[] = ([
      {myProperty: [["Hello", "World"], []]},
      {myProperty: [["Hello"], []]},
  ] as MyType[]).sort(compareMyType);
  const array5: MyType[] = ([
      {myProperty: [["Hello", "World"], []]},
      {myProperty: 5},
  ] as MyType[]).sort(compareMyType);
  

  Casting supresses errors which can cause runtime errors

• Sorting already initialized array

  const array1: MyType[] = [
  
      const array2: MyType[] = [
      {myProperty: [["Hello", "World"], []]},
      {myProperty: [["Hello"], []]},
  ];
  
  const array6: MyType[] = array1.sort(compareMyType);
  

  No errors.

Why is this working, while the other attempts are not (compiler or runtime errors)? Are there better/other workarounds?

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