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Match Erlang semantics for div/2 and round/1 #500

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5 changes: 2 additions & 3 deletions src/javascript/lib/core/erlang_compat/erlang.js
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Original file line number Diff line number Diff line change
Expand Up @@ -164,7 +164,7 @@ function equals(left, right) {
}

function div(left, right) {
return left / right;
return Math.trunc(left / right);
}

function not(x) {
Expand Down Expand Up @@ -357,7 +357,7 @@ function min(first, second) {
}

function round(number) {
return Math.round(number);
return Math.sign(number) * Math.round(Math.abs(number));
}

function tl(list) {
Expand Down Expand Up @@ -463,7 +463,6 @@ function nodes(arg = []) {
for (const nodeType of nodeTypes) {
if (nodeType === Symbol.for('this')) {
nodesFound.push(Symbol.for('nonode@nohost'));
console.log(nodesFound);
}
}
return nodesFound;
Expand Down
30 changes: 30 additions & 0 deletions src/javascript/tests/core/erlang_compat/erlang_spec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,36 @@ test('list_subtraction', (t) => {
t.deepEqual(Core.erlang.list_subtraction([1, 2, 3], [1, 2]), [3]);
});

test('div', (t) => {
t.is(Core.erlang.div(6, 3), 2);
t.is(Core.erlang.div(7, 2), 3);
t.is(Core.erlang.div(-7, 2), -3);
t.is(Core.erlang.div(7, -2), -3);
t.is(Core.erlang.div(-7, -2), 3);
});

test('rem', (t) => {
t.is(Core.erlang.rem(7, 2), 1);
t.is(Core.erlang.rem(-7, 2), -1);
t.is(Core.erlang.rem(7, -2), 1);
t.is(Core.erlang.rem(-7, -2), -1);
});

test('round', (t) => {
t.is(Core.erlang.round(1.4), 1);
t.is(Core.erlang.round(2.5), 3);
t.is(Core.erlang.round(-2.5), -3);
t.is(Core.erlang.round(0.5), 1);
t.is(Core.erlang.round(-0.5), -1);
t.is(Core.erlang.round(4), 4);
t.is(Core.erlang.round(-4), -4);
});

test('trunc', (t) => {
t.is(Core.erlang.trunc(2.7), 2);
t.is(Core.erlang.trunc(-2.7), -2);
});

test('node', (t) => {
t.deepEqual(Core.erlang.node(), Symbol.for('nonode@nohost'));
});
Expand Down