V8 Collection#

Collection in V8#

Javet provides decent support on manipulating V8 collection as following.

Collection

getLength() / getSize()

add() / set()

delete()

has()

get()

getKeys() / getOwnPropertyNames()

getValues()

getEntries()

forEach(Consumer)

forEach(BiConsumer)

Object

No

Yes

yes

Yes

Yes

Yes

No

No

Yes

Yes

Array

Yes

Yes

yes

Yes

Yes

Yes

No

No

Yes

No

Map

Yes

Yes

yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Set

Yes

Yes

yes

Yes

Yes

Yes

No

No

Yes

No

WeakMap

No

Yes

yes

Yes

Yes

No

No

No

No

No

WeakSet

No

Yes

yes

Yes

No

No

No

No

No

No

Usage#

V8ValueArray#

try (V8ValueArray v8ValueArray = v8Runtime.getExecutor("const a = new Array(0,1,2); a;").execute()) {
    AtomicInteger count = new AtomicInteger(0);
    v8ValueArray.forEach((V8ValueInteger value) -> {
        assertEquals(count.getAndIncrement(), value.getValue());
    });
    assertEquals(4, v8ValueArray.push(3));
    assertEquals(3, v8ValueArray.popInteger());
}

V8ValueSet#

try (V8ValueSet v8ValueSet = v8Runtime.getExecutor(
        "const a = new Set(); a.add('0'); a.add('1'); a.add('2'); a;").execute()) {
    // V8 feature: Order is preserved.
    AtomicInteger count = new AtomicInteger(0);
    assertEquals(3, v8ValueSet.forEach((V8ValueString key) -> {
        assertEquals(Integer.toString(count.getAndIncrement()), key.getValue());
    }));
    v8ValueSet.add("3");
    assertTrue(v8ValueSet.has("3"));
    assertTrue(v8ValueSet.delete("3"));
    assertFalse(v8ValueSet.has("3"));
}

V8ValueMap#

try (V8ValueMap v8ValueMap = v8Runtime.getExecutor(
        "const a = new Map(); a.set('0', 0); a.set('1', 1); a.set('2', 2); a;").execute()) {
    // V8 feature: Order is preserved.
    AtomicInteger count = new AtomicInteger(0);
    assertEquals(3, v8ValueMap.forEach((V8ValueString key) -> {
        assertNotNull(key);
        assertEquals(Integer.toString(count.getAndIncrement()), key.getValue());
    }));
    count.set(0);
    assertEquals(3, v8ValueMap.forEach((V8ValueString key, V8ValueInteger value) -> {
        assertNotNull(key);
        assertNotNull(value);
        assertEquals(Integer.toString(count.get()), key.getValue());
        assertEquals(count.getAndIncrement(), value.getValue());
    }));
    v8ValueMap.set("a", 1);
    assertEquals(4, v8ValueMap.getSize());
    assertTrue(v8ValueMap.has("a"));
    assertTrue(v8ValueMap.delete("a"));
}