diff --git a/vlib/builtin/js/array.js.v b/vlib/builtin/js/array.js.v
index 4a342d5272..651e366b92 100644
--- a/vlib/builtin/js/array.js.v
+++ b/vlib/builtin/js/array.js.v
@@ -149,3 +149,14 @@ pub fn (mut a array) delete(i int) {
 pub fn (mut a array) delete_many(i int, size int) {
 	#a.arr.splice(i.valueOf(),size.valueOf())
 }
+
+// prepend prepends one value to the array.
+pub fn (mut a array) prepend(val voidptr) {
+	a.insert(0, val)
+}
+
+// prepend_many prepends another array to this array.
+[unsafe]
+pub fn (mut a array) prepend_many(val voidptr, size int) {
+	unsafe { a.insert_many(0, val, size) }
+}
diff --git a/vlib/v/gen/js/js.v b/vlib/v/gen/js/js.v
index d6b029767a..0119224e71 100644
--- a/vlib/v/gen/js/js.v
+++ b/vlib/v/gen/js/js.v
@@ -1444,6 +1444,26 @@ fn (mut g JsGen) gen_call_expr(it ast.CallExpr) {
 					g.write(')')
 					return
 				}
+				'prepend' {
+					arg_sym := g.table.get_type_symbol(node.args[0].typ)
+					is_arg_array := arg_sym.kind == .array && node.args[0].typ == node.left_type
+					if is_arg_array {
+						g.write('prepend_many(')
+					} else {
+						g.write('prepend(')
+					}
+
+					if is_arg_array {
+						g.expr(node.args[0].expr)
+						g.write('.arr, ')
+						g.expr(node.args[0].expr)
+						g.write('.len')
+					} else {
+						g.expr(node.args[0].expr)
+					}
+					g.write(')')
+					return
+				}
 				else {}
 			}
 		}
@@ -1975,7 +1995,7 @@ fn (mut g JsGen) gen_integer_literal_expr(it ast.IntegerLiteral) {
 	// Skip cast if type is the same as the parrent caster
 	if g.cast_stack.len > 0 {
 		if g.cast_stack[g.cast_stack.len - 1] in ast.integer_type_idxs {
-			g.write('$it.val')
+			g.write('new int($it.val)')
 			return
 		}
 	}
@@ -2013,7 +2033,7 @@ fn (mut g JsGen) gen_float_literal_expr(it ast.FloatLiteral) {
 	// Skip cast if type is the same as the parrent caster
 	if g.cast_stack.len > 0 {
 		if g.cast_stack[g.cast_stack.len - 1] in ast.float_type_idxs {
-			g.write('$it.val')
+			g.write('new f32($it.val)')
 			return
 		} else if g.cast_stack[g.cast_stack.len - 1] in ast.integer_type_idxs {
 			g.write(int(it.val.f64()).str())
diff --git a/vlib/v/gen/js/tests/testdata/array.out b/vlib/v/gen/js/tests/testdata/array.out
index 134a2cfeb3..ffeaeacc6a 100644
--- a/vlib/v/gen/js/tests/testdata/array.out
+++ b/vlib/v/gen/js/tests/testdata/array.out
@@ -61,4 +61,51 @@ true
 1
 1.1
 [1,2,3,4]
-[1,5,6,2,3,4]
\ No newline at end of file
+[1,5,6,2,3,4]
+0
+1
+1
+0
+1
+1.1
+[1,2,3,4]
+[5,6,1,2,3,4]
+5
+true
+1.1
+1.1
+1.1
+-123
+-123
+-123
+123
+123
+123
+1.1
+1.1
+1.1
+1
+2
+1
+2
+1
+abc
+1
+abc
+0
+abc
+2
+3
+2
+3
+1
+2
+1
+2
+2
+1
+4
+6
+1
+4
+6
\ No newline at end of file
diff --git a/vlib/v/gen/js/tests/testdata/array.v b/vlib/v/gen/js/tests/testdata/array.v
index bc23e9264f..3278bd46ce 100644
--- a/vlib/v/gen/js/tests/testdata/array.v
+++ b/vlib/v/gen/js/tests/testdata/array.v
@@ -183,4 +183,140 @@ fn main() {
 		a.insert(1, b)
 		println(a)
 	}
+	{
+		// test prepend
+		mut a := []int{}
+		println(a.len)
+		a.prepend(1)
+		println(a.len)
+		println(a[0])
+		mut b := []f64{}
+
+		println(b.len)
+
+		b.prepend(f64(1.1))
+
+		println(b.len)
+
+		println(b[0])
+	}
+	{
+		// test prepend many
+		mut a := [3, 4]
+		a.prepend([1, 2])
+		println(a)
+		b := [5, 6]
+		a.prepend(b)
+		println(a)
+	}
+	{
+		// test repeat
+		{
+			a := [0].repeat(5)
+			println(a.len)
+			println(a[0] == 0 && a[1] == 0 && a[2] == 0 && a[3] == 0 && a[4] == 0)
+		}
+		{
+			a := [1.1].repeat(10)
+			println(a[0])
+			println(a[5])
+			println(a[9])
+		}
+		{
+			a := [i64(-123)].repeat(10)
+			println(a[0])
+			println(a[5])
+			println(a[9])
+		}
+		{
+			a := [u64(123)].repeat(10)
+			println(a[0])
+			println(a[5])
+			println(a[9])
+		}
+		{
+			a := [1.1].repeat(10)
+			println(a[0])
+			println(a[5])
+			println(a[9])
+		}
+		{
+			a := [1, 2].repeat(2)
+			println(a[0])
+			println(a[1])
+			println(a[2])
+			println(a[3])
+		}
+		{
+			a := ['1', 'abc'].repeat(2)
+			println(a[0])
+			println(a[1])
+			println(a[2])
+			println(a[3])
+		}
+		{
+			mut a := ['1', 'abc'].repeat(0)
+			println(a.len)
+			a << 'abc'
+			println(a[0])
+		}
+	}
+	{
+		/*
+		// test deep repeat
+		mut a3 := [[[1, 1], [2, 2], [3, 3]], [[4, 4], [5, 5], [6, 6]]]
+		r := a3.repeat(3)
+		a3[1][1][0] = 17
+		print(r)
+		assert r == [
+			[[1, 1], [2, 2], [3, 3]],
+			[[4, 4], [5, 5], [6, 6]],
+			[[1, 1], [2, 2], [3, 3]],
+			[[4, 4], [5, 5], [6, 6]],
+			[[1, 1], [2, 2], [3, 3]],
+			[[4, 4], [5, 5], [6, 6]],
+		]
+		assert a3 == [[[1, 1], [2, 2], [3, 3]], [[4, 4], [17, 5],
+			[6, 6],
+		]]
+		*/
+	}
+	{
+		// test right
+		a := [1, 2, 3, 4]
+		c := a[1..a.len]
+		d := a[1..]
+		println(c[0])
+		println(c[1])
+		println(d[0])
+		println(d[1])
+	}
+	{
+		// test left
+		a := [1, 2, 3]
+		c := a[0..2]
+		d := a[..2]
+		println(c[0])
+		println(c[1])
+		println(d[0])
+		println(d[1])
+	}
+	{
+		// test slice
+		a := [1, 2, 3, 4]
+		b := a[2..4]
+		println(b.len)
+		println(a[1..2].len)
+		println(a.len)
+	}
+	{
+		// test push many
+		mut a := [1, 2, 3]
+		b := [4, 5, 6]
+		a << b
+		println(a.len)
+		println(a[0])
+		println(a[3])
+		println(a[5])
+	}
 }