Simple vector implementation in js to help with amortized analysis

vector.js

function Vector() {
	this.capacity = 1;
	this.elements = new Array(this.capacity);
	this.size = 0;
	
	this.add = (element) => {
		if (this.size > this.capacity)
			console.err('this.size > this.capacity');
		
		if (this.size === this.capacity) {
			this.capacity *= 2;
			let t = new Array(this.capacity);
			for(let i = 0; i < this.size; i++) {
				t[i] = this.elements[i];
			}
			this.elements = t;
		}
		
		this.elements[this.size++] = element;
	};
	
	this.get = (i) => {
		return this.elements[i];
	}
}