How to remove TypeScript warning: property 'length' does not exist on type '{}'

Question

In a TypeScript file, I have defined a 3D array:

var myArr = ['one', [[19, 1], [13, 1], [86, 1], [12, 2]],              'two',    [[83, 1], [72, 1], [16, 2]],              'three',  [[4, 1]]];  function testArray(){     console.log(myArr[1].length); } 

I get a warning under the length property:

Property 'length' does not exist on type '{}'

Is there something I can do to remove this warning?

Answer 1

I read a similar post here: How can I stop "property does not exist on type JQuery" syntax errors when using Typescript?

Which explains that I can cast to <any>.

This worked for me:

function testArray(){     console.log((<any>myArr[1]).length); } 

Answer 2

Option 1: upgrade to bleeding-edge compiler and get union types

Option 2: Add a type annotation to the variable declaration:

var myArr: any[] = ['one', [[19, 1], [13, 1], [86, 1], [12, 2]],              'two',    [[83, 1], [72, 1], [16, 2]],              'three',  [[4, 1]]];  function testArray(){     console.log(myArr[1].length); }