1function sum(a, b) { return a + b; }

1// Can be named:
2(function sum(a, b) { 
3    return a + b;
4}); 
5
6// Or anonymous (AVOID):
7(function(a, b) { 
8     return a + b; 
9 });
10 // Or assigned to a variable
11const sum = function sum(a, b) { 
12     return a + b; 
13  })

1// Single argument, one line return:
2    name => name.split(' ');
3
4// Multi arguments, one line return:
5    (a, b) => a + b; 
6
7// Single argument, full body:
8name => { 
9    return name.split(' '); 
10}
11
12// Regular:
13    (a, b) => { return a + b };

1function *sum(a, b) { yield a + b; };

1async function sum(a, b) { 
2    return await a + b; 
3};

1new Function(‘a’, ‘b’, ‘return a + b;’);

1// Default exports
2export default function(a, b) { 
3    return a + b; 
4};
5
6// Named exports
7export function sum(a, b) { 
8    return a + b; 
9};

1// Regular:
2const object = {
3  sum: function(a, b) { 
4      return a + b; 
5  },
6};
7
8// Shorthand:
9const object = {
10  sum(a, b) { 
11      return a + b; 
12  },
13};

1const functionName = "sum";
2
3const object = {
4  [functionName]: function(a, b) { 
5      return a + b; 
6  },
7};

1// Regular:
2const object = {
3  get answer { 
4      return 42; 
5  },
6  set answer(value) { /* do something with value */ },
7};
8
9// With defineProperty
10const obj = {};
11
12Object.defineProperty(obj, "answer", {
13  get() { 
14      return 42; 
15  },
16  set(value) { /* do something with value */ },
17});

1const functionName = "answer";
2
3const object = {
4  get [functionName]() { 
5      return 42; 
6  },
7  
8  set [functionName](value) { /* do something with value */ },
9};

1class Compute {
2  // Regular:
3  sum(a, b) { 
4      return a + b; 
5  };
6};
7
8class Compute {
9  // Static:
10  static sum(a, b) { 
11      return a + b; 
12  };
13}

1class Compute {
2  // Regular:
3  sum = function (a, b) { 
4      return a + b; 
5  };
6};
7
8class Compute {
9  // Static:
10  static sum = function(a, b) { 
11  return a + b; 
12  };
13}

1class Compute {
2  // Regular:
3  #sum(a, b) {
4    return a + b;
5  }  
6  
7  // Static:
8  static #sum(a, b) {
9    return a + b;
10  }
11}