JavaScript to replace variable in a string

Question

I want to write a function to replace variables in a string with actual values, for example:

function replaceUrl(url, data) {}

The caller may be:

replaceUrl('/task/:module?taskId=:taskId#:hash', {
    module: 'm1',
    taskId: 't1',
    hash: 'h1'
});

I think to use RegEx may be simple to implement this, but I'm not very familiar with it.

Can anyone provide a simple way on this?

Answer 1

A simple solution is not to use RegEx at all. Use Template literals

var module = 'm1',
    taskId = 't1',
    hash   = 'h1';

var url = `/task/${module}?taskId=${taskId}#${hash}`;

var module = 'm1',
    taskId = 't1',
    hash = 'h1';

var url = `/task/${module}?taskId=${taskId}#${hash}`;

document.body.innerHTML = url;

Using RegEx:

function replaceUrl(url, data) {
    // Create regex using the keys of the replacement object.
    var regex = new RegExp(':(' + Object.keys(data).join('|') + ')', 'g');

    // Replace the string by the value in object
    return url.replace(regex, (m, $1) => data[$1] || m);
}

function replaceUrl(url, data) {
    var regex = new RegExp(':(' + Object.keys(data).join('|') + ')', 'g');

    return url.replace(regex, (m, $1) => data[$1] || m);
}


var updatedUrl = replaceUrl('/task/:module?taskId=:taskId#:hash', {
    module: 'm1',
    taskId: 't1',
    hash: 'h1'
});

console.log(updatedUrl);
document.body.innerHTML = updatedUrl;