indexof slice splice
a=[1,2,3,4,5,6];
b=[100,200,[11,22,33]];
console.log(a.indexOf(3));
console.log(b.indexOf(22));
console.log(a.slice(3,5));
console.log(a.slice(3));
console.log(b.splice(1,2));
console.log(a);
console.log(b);
a.splice(4);
console.log(a);
2 debugger eval code:3:9
-1 debugger eval code:4:9
Array [ 4, 5 ]
debugger eval code:5:9
Array(3) [ 4, 5, 6 ]
debugger eval code:6:9
Array [ 200, (3) […] ]
debugger eval code:7:9
Array(6) [ 1, 2, 3, 4, 5, 6 ]
debugger eval code:8:9
Array [ 100 ]
debugger eval code:9:9
Array(4) [ 1, 2, 3, 4 ]