Like this:

const var1 = 'dynFuncName';
const obj = { [var1]() { throw 'error' } };
// or const obj = { [var1]: function() { throw 'error' } };
// or const obj = { [var1]: () => { throw 'error' } };

const fn = obj[var1];
fn();

Results in the following console error message:

VM83:5 Uncaught error
dynFuncName @   VM83:5
(anonymous) @   VM83:9
(anonymous) @   VM83:10

As per:

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/name#variable_declaration_and_method