Detox get length of element - react-native

Question

Hi i'm using detox and i would like to know how can I get the number of matches to
one element(length).
For example "card" match three times, how can I get the three.
const z = await element(by.id("card"))
https://github.com/wix/Detox/blob/master/docs/APIRef.Expect.md
https://github.com/wix/Detox/blob/master/docs/APIRef.Matchers.md
They don't support it in the API /:
z output:
Element {
_invocationManager: InvocationManager {
executionHandler: Client {
isConnected: true,
configuration: [Object],
ws: [AsyncWebSocket],
slowInvocationStatusHandler: null,
slowInvocationTimeout: undefined,
successfulTestRun: true,
pandingAppCrash: undefined
}
},
matcher: Matcher { predicate: { type: 'id', value: 'card' } }
}

Answer 1

A workaround could be
async function getMatchesLength(elID) {
let index = 0;
try {
while (true) {
await expect(element(by.id(elID)).atIndex(index)).toExist();
index++;
}
} catch (error) {
console.log('find ', index, 'matches');
}
return index;
}
then you can use
const length = await getMatchesLength('card');
jestExpect(length).toBe(3);

Answer 2

Here is my solution in typescript:
async function elementCount(matcher: Detox.NativeMatcher) {
const attributes = await element(matcher).getAttributes();
// If the query matches multiple elements, the attributes of all matched elements is returned as an array of objects under the elements key.
https://wix.github.io/Detox/docs/api/actions-on-element/#getattributes
if ("elements" in attributes) {
return attributes.elements.length;
} else {
return 1;
}
}
Then you can use it like this:
const jestExpect = require("expect");
jestExpect(await elementCount(by.id("some-id"))).toBe(2);