JavaScript替换多个if语句

Question

I have couple of identical html pages and I would like to use the same JavaScript file which reads text files and changes data on the html pages. As the text files are different for every page I have done it with multiple if statements. It would be better if there is a way to replace it with some loop?

if (window.location.pathname=='/myapp/main.html') {
  $.get('data/data1.txt', function(data) {
     var bigarray = data.split('\n');
     bigarray.forEach(function(currRow){
       currentRow = currRow.split(';');
       table.push(currentRow);});
  }, 'text');
}

if (window.location.pathname=='/myapp/main2.html') {
  $.get('data/data2.txt', function(data) {
     var bigarray = data.split('\n');
     bigarray.forEach(function(currRow){
       currentRow = currRow.split(';');
       table.push(currentRow);});
  }, 'text');
}

if (window.location.pathname=='/myapp/main3.html') {
  $.get('data/data3.txt', function(data) {
     var bigarray = data.split('\n');
     bigarray.forEach(function(currRow){
       currentRow = currRow.split(';');
       table.push(currentRow);});
  }, 'text');
}

if (window.location.pathname=='/myapp/main4.html') {
  $.get('data/data4.txt', function(data) {
     var bigarray = data.split('\n');
     bigarray.forEach(function(currRow){
       currentRow = currRow.split(';');
       table.push(currentRow);});
  }, 'text');
}

Thank you in advance!

Answer 1

So either use an object

var paths = {
 "/myapp/main.html" : "data/data1.txt",
 "/myapp/main2.html" : "data/data2.txt",
 "/myapp/main3.html" : "data/data3.txt",
 "/myapp/main4.html" : "data/data4.txt"
};

var filePath = paths[window.location.pathname];
if (filePath) {
  $.get(filePath, ...)
}

or use a reg exp to match the number and use that if the paths are the same.

Answer 2

Since your paths have the same structure, you could simply use a regex to get the number.

With that you can create new pages/data as you go, and it will just pick them up automatically.

if (window.location.pathname.startsWith('/myapp/main') {  // this "if" might not be needed

  var pathnum = window.location.pathname.replace(/[^0-9]/g,'');

  $.get('data/data' + pathnum + '.txt', function(data) {
     var bigarray = data.split('\n');
     bigarray.forEach(function(currRow){
       currentRow = currRow.split(';');
       table.push(currentRow);});
  }, 'text');

}

---

And if no number as in main.html should use data1.txt , you can do something like this

  $.get('data/data' + (pathnum == '' ? 1 : pathnum) + '.txt', function(data) {

Answer 3

Created a simple reusable function that accepts a path and a data url:

 const getData = (path, url) => { if (window.location.pathname === path ) { $.get(url, function(data) { var bigarray = data.split('\\n'); bigarray.forEach(function(currRow){ currentRow = currRow.split(';'); table.push(currentRow);}); }, 'text'); } } // Usage getData('/myapp/main.html', 'data/data1.txt'); getData('/myapp/main2.html', 'data/data2.txt'); getData('/myapp/main3.html', 'data/data3.txt'); getData('/myapp/main4.html', 'data/data4.txt'); 

Answer 4

You could use template literals.

Docs: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals

function changeText() {
    const toString = Object.prototype.toString;
    const { pathname } = window.location;

    // Get the index of the dot
    const dot = pathname.search('.');

    // Grab the character immediately preceding the dot
    const testChar = pathname.charAt(dot-1);

    // If the character is not a number, set the index to 1
    const index = toString.call(testChar) === '[object Number]'
        ? testChar
        : 1;

  // Use the template literal
  $.get(`data/data${index}.txt`, function(data) {
     var bigarray = data.split('\n');
     bigarray.forEach(function(currRow){
       currentRow = currRow.split(';');
       table.push(currentRow);});
  }, 'text');

}

The method requires no looping or custom text. Usage is simply: changeText() .