JavaScript: Fill an array with values on supplied bounds

JavaScript Array: Exercise-29 with Solution

Fill Array with Values

Write a JavaScript function to fill an array with values (numeric, string with one character) within supplied bounds.

Test Data:
console.log(num_string_range('a', "z", 2));
["a", "c", "e", "g", "i", "k", "m", "o", "q", "s", "u", "w", "y"]

Sample Solution:

JavaScript Code:

// Function to generate a range of numbers or characters based on start, end, and step
function num_string_range(start, end, step) {
  // Initialize an empty array 'range' to store the generated range
  var range = [];

  // Check for invalid step value or undefined start/end values
  if ((step === 0) || (typeof start === "undefined" || typeof end === "undefined") || (typeof start !== typeof end))
    return false;

  // Adjust the step direction if end is less than start
  if (end < start) {
    step = -step;
  }

  // Check if the start value is a number
  if (typeof start === "number") {
    // Generate a range of numbers
    while (step > 0 ? end >= start : end <= start) {
      range.push(start);
      start += step;
    }
  } 
  // Check if the start value is a string
  else if (typeof start === "string") {
    // Check if both start and end are single characters
    if (start.length !== 1 || end.length !== 1) {
      throw TypeError("Strings with one character are supported.");
    }

    // Convert characters to their ASCII codes
    start = start.charCodeAt(0);
    end = end.charCodeAt(0);

    // Generate a range of characters
    while (step > 0 ? end >= start : end <= start) {
      range.push(String.fromCharCode(start));
      start += step;
    }
  } 
  // Throw an error for unsupported types
  else {
    throw TypeError("Only string and number are supported");
  }

  // Return the generated range
  return range;
}

// Output the result of the num_string_range function with sample inputs
console.log(num_string_range('a', "z", 2));
console.log(num_string_range("Z", "A", 2));
console.log(num_string_range(0, -5, 1));
console.log(num_string_range(0, 25, 5));
console.log(num_string_range(20, 5, 5));

Output:

["a","c","e","g","i","k","m","o","q","s","u","w","y"]
["Z","X","V","T","R","P","N","L","J","H","F","D","B"]
[0,-1,-2,-3,-4,-5]
[0,5,10,15,20,25]
[20,15,10,5]

Flowchart:

ES6 Version:

// Function to generate a range of numbers or characters based on start, end, and step
const num_string_range = (start, end, step) => {
  // Initialize an empty array 'range' to store the generated range
  const range = [];

  // Check for invalid step value or undefined start/end values
  if ((step === 0) || (typeof start === "undefined" || typeof end === "undefined") || (typeof start !== typeof end))
    return false;

  // Adjust the step direction if end is less than start
  if (end < start) {
    step = -step;
  }

  // Check if the start value is a number
  if (typeof start === "number") {
    // Generate a range of numbers
    while (step > 0 ? end >= start : end <= start) {
      range.push(start);
      start += step;
    }
  } 
  // Check if the start value is a string
  else if (typeof start === "string") {
    // Check if both start and end are single characters
    if (start.length !== 1 || end.length !== 1) {
      throw TypeError("Strings with one character are supported.");
    }

    // Convert characters to their ASCII codes
    start = start.charCodeAt(0);
    end = end.charCodeAt(0);

    // Generate a range of characters
    while (step > 0 ? end >= start : end <= start) {
      range.push(String.fromCharCode(start));
      start += step;
    }
  } 
  // Throw an error for unsupported types
  else {
    throw TypeError("Only string and number are supported");
  }

  // Return the generated range
  return range;
};

// Output the result of the num_string_range function with sample inputs
console.log(num_string_range('a', "z", 2));
console.log(num_string_range("Z", "A", 2));
console.log(num_string_range(0, -5, 1));
console.log(num_string_range(0, 25, 5));
console.log(num_string_range(20, 5, 5));

Live Demo:

See the Pen JavaScript - Fill an array with values on supplied bounds - array-ex- 29 by w3resource (@w3resource) on CodePen.

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