local-link/index.js

Determine which link clicks should be captured for client-side navigation

module.exports = function (ev) {    
    if (ev.which > 1 || ev.altKey || ev.ctrlKey || ev.metaKey || ev.shiftKey || ev.defaultPrevented) {
        return;
    }
    
    var anchor = null;
    for (var n = ev.target; n; n = n.parentNode) {
        if (n.nodeName === 'A') {
            anchor = n;
            break;
        }
    }

    if (!anchor) return;

    if (anchor.target && anchor.target.toLowerCase() !== '_self') return;

    // IE clears the host value if the anchor href changed after creation, e.g. in React
    // Creating a new anchor element to insure host value is present
    var a1 = document.createElement('a');
    a1.href = anchor.href;
    
    // In IE, the default port is included in the anchor host but excluded from the location host.
    // This affects the ability to directly compare location host to anchor host.
    // For example: http://example.com would have a location.host of 'example.com' and an anchor.host of 'example.com:80'
    // Creating anchor from the location.href to normalize the host value.
    var a2 = document.createElement('a');
    a2.href = location.href;

    if (a1.host !== a2.host || a1.protocol !== a2.protocol) return;

    return anchor;
};