React Native Requires Chilkat v11.4.0+

Call a JavaScript Function Returning an Array

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Demonstrates how to call a JavaScript function that returns an array. React Native

import { Js, JsonObject, StringBuilder } from '@chilkat/react-native'

async function chilkatExample() {
  // ----------------------------------------------------------------------------------
  // The Javascript functions called in this example are shown at the bottom of this page.
  // -----------------------------------------------------------------------------------

  const sbScript = new StringBuilder();
  try {
    sbScript.loadFile('js_function_returning_array.js', 'utf-8');
  } catch {
    console.log(sbScript.lastErrorText);
    return;
  }

  const js = new Js();

  const result = new JsonObject();
  result.emitCompact = false;

  // Call Eval to add the function to the context's global object
  try {
    await js.evalAsync(sbScript, result);
  } catch {
    // Examine the result for an exception.
    console.log(result.emit());

    // Also examine the LastErrorText.
    console.log(js.lastErrorText);
    return;
  }

  // ------------------------------------------------------------------------------
  // Call each function

  const funcCall = new JsonObject();

  // Create JSON specifying the function name and arguments
  // The function has no arguments, so we only specify the name.

  funcCall.updateString('name', 'getDays');

  try {
    await js.callFunctionAsync(funcCall, result);
  } catch {
    // Examine the result for an exception.
    console.log(result.emit());

    // Also examine the LastErrorText.
    console.log(js.lastErrorText);
    return;
  }

  console.log(result.emit());

  // Output:
  // {
  //   "type": "array",
  //   "value": [
  //     "Monday",
  //     "Tuesday",
  //     "Wednesday",
  //     "Thursday",
  //     "Friday"
  //   ]
  // }

  // Access each array value..
  let count = result.sizeOfArray('value');
  let i = 0;
  while (i < count) {
    result.i = i;
    console.log(result.stringOf('value[i]'));
    i++;
  }

  // ------------------------------------------------------------------------------
  // Call the getRange(start,end) function

  funcCall.clear();
  funcCall.updateString('name', 'getRange');
  funcCall.updateInt('args[0]', 14);
  funcCall.updateInt('args[1]', 21);
  await js.callFunctionAsync(funcCall, result);
  console.log(result.emit());

  // Output:
  // {
  //   "type": "array",
  //   "value": [
  //     14,
  //     15,
  //     16,
  //     17,
  //     18,
  //     19,
  //     20,
  //     21
  //   ]
  // }

  count = result.sizeOfArray('value');
  i = 0;
  while (i < count) {
    result.i = i;
    console.log(result.intOf('value[i]'));
    i++;
  }

  // ------------------------------------------------------------------------------
  // Call the getEmployees() function

  funcCall.clear();
  funcCall.updateString('name', 'getEmployees');
  await js.callFunctionAsync(funcCall, result);
  console.log(result.emit());

  // Output:
  // {
  //   "type": "array",
  //   "value": [
  //     {
  //       "id": 101,
  //       "name": "Alice",
  //       "role": "Dev"
  //     },
  //     {
  //       "id": 102,
  //       "name": "Bob",
  //       "role": "Manager"
  //     }
  //   ]
  // }

  count = result.sizeOfArray('value');
  i = 0;
  while (i < count) {
    result.i = i;
    console.log(`name: ${result.stringOf('value[i].name')}`);
    console.log(`role: ${result.stringOf('value[i].role')}`);
    console.log(`id: ${result.intOf('value[i].id')}`);
    console.log('');
    i++;
  }
}

JavaScript

function getDays() {
    return ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"];
}

function getRange(start, end) {
    var arr = [];
    for (var i = start; i <= end; i++) {
        arr.push(i);
    }
    return arr;
}
// Usage: getRange(1, 5) -> [1, 2, 3, 4, 5]

function getEmployees() {
    return [
        { id: 101, name: "Alice", role: "Dev" },
        { id: 102, name: "Bob", role: "Manager" }
    ];
}