如何在JavaScript中实现类似PHP常量MODE_B2B_B2C的条件判断

Got it, let's break down how to replicate that PHP conditional check in JavaScript. First, your PHP code checks if the MODE_B2B_B2C constant is set to 'true', then adds a table header cell to your content. Here's how to do the same in JS, including getting that PHP constant into your client-side code.

First: Pass the PHP Constant to JavaScript #

Since JavaScript runs in the browser, you need to inject the value of MODE_B2B_B2C from your PHP backend into your JS script. You can do this directly when rendering the page:

<script type="text/javascript">
// Pull the PHP constant into a JS variable
const MODE_B2B_B2C = '<?php echo MODE_B2B_B2C; ?>';
// Rest of your JS code goes here...
</script>

If MODE_B2B_B2C is a boolean in PHP (not a string), you can output it as a JS boolean instead for cleaner comparisons:

const MODE_B2B_B2C = <?php echo MODE_B2B_B2C ? 'true' : 'false'; ?>;

Second: Write the Conditional Logic in JS #

Now that you have the constant available, here's how to mirror your PHP logic:

Option 1: Dynamically Add the Table Cell (Like Your PHP Code) #

If you want to add that table header cell to an existing row in the DOM, use this:

// Grab the table row you want to modify (adjust the selector to match your HTML)
const targetRow = document.querySelector('tr');

if (MODE_B2B_B2C === 'true') { // Or just `=== true` if you used the boolean version
  // Create the <td> element
  const headerCell = document.createElement('td');
  // Set its text (inject the translated text from PHP here too)
  headerCell.textContent = '<?php echo $this->app->getDef('table_heading_customers_group'); ?>';
  // Add the cell to the row
  targetRow.appendChild(headerCell);
}

Option 2: Use the Condition in Your Existing JS Function #

Looking at your snippet, you have a quantitydiscount_row variable. If you need to use the condition within that context, here's an example:

var quantitydiscount_row = <?php echo $i; ?>;

// Check the mode and run your logic
if (MODE_B2B_B2C === 'true') {
  // Do whatever you need here—like update a DOM element, calculate values, etc.
  console.log('B2B/B2C mode is active');
}

Quick Tip: #

In JavaScript, always prefer strict equality (===) over loose equality (==) to avoid weird type coercion bugs. It's the same best practice as using === in modern PHP.

内容的提问来源于stack exchange，提问作者Zigoto