Fix: Routing aliases

[Bengejd]

Relevant Issues:

#1108, #403, #885

Reasoning for PR

Compodoc has had this long-standing issue for quite some time now, and it's baring the entry for a lot of companies to utilize this library. The majority of mid-sized+ companies will utilize aliases for imports. Previously, the current work-around was to simply use relative imports for the routes:

../core/components/somecomponent/somecomponent.route.ts

instead of a nice import path of:

app/core/components/somecomponent/somecomponent.route.ts

This doesn't look like that big of a deal, but when you're importing sibling & nested routes, it becomes quite the hassle at scale.

In my case, I was originally receiving a path with the value of:

C:/Users/Benge/Documents/GitHub/@myclient/src/app/app/core/components/patients-list/patients-list.routes.ts

With the issue being

.../app/app/...

because while .../app/core/... is a existing file path, .../app/app/core/... is not.

Cause of issue

let importPath = path.resolve(
                        path.dirname(file.getFilePath()) +
                            '/' +
                            searchedImport.getModuleSpecifierValue() +
                            '.ts'
                    );

With path.dirname(file.getFilePath() having a value of C:/Users/Benge/Documents/GitHub/@myclient/src/app and searchedImport.getModuleSpecifierValue() having a value of app/core/components/patients-list/patients-list.routes.ts

Solution

My solution is simply a bandaid until a more long-term fix of the route-parser can be implemented, but to break it down:

// Reusable function to check to see if the path is bad or not. Can be inlined since it's only used once now.
const routePathIsBad = (path) => {
    return typeof ast.getSourceFile(path) == 'undefined';
};

// Returns an array of indicies for a given string.
const getIndicesOf = (searchStr, str, caseSensitive) => {
    var searchStrLen = searchStr.length;
    if (searchStrLen == 0) {
        return [];
    }
    var startIndex = 0, index, indices = [];
    if (!caseSensitive) {
        str = str.toLowerCase();
        searchStr = searchStr.toLowerCase();
    }
    while ((index = str.indexOf(searchStr, startIndex)) > -1) {
        indices.push(index);
        startIndex = index + searchStrLen;
    }
    return indices;
}

// Should probably be a constant for easier debugging in the future.
const dirNamePath = path.dirname(file.getFilePath());

// Should probably be a constant for easier debugging in the future.
const searchedImportPath = searchedImport.getModuleSpecifierValue();

// Grabs the leading folder name from the import Path and returns it. `app/core/components` would return `app`
const leadingFilePath = searchedImportPath.split('/').shift();

// Set the importPath like usual
let importPath = path.resolve(dirNamePath + '/' + searchedImport.getModuleSpecifierValue() + '.ts');

// Check to see if the path is bad or not. 
if (routePathIsBad(importPath)) {

   // Grab the indexes of leadingFilePath that are in importPath
    let leadingIndices = getIndicesOf(leadingFilePath, importPath, true);
    if (leadingIndices.length > 1) { // Nested route fixes
        let startIndex = leadingIndices[0];
        let endIndex = leadingIndices[leadingIndices.length -1];
        
        // Recreate the string from the two pieces 
        importPath = importPath.slice(0, startIndex) + importPath.slice(endIndex);
    } else { // Top level route fixes
        // Grab the parent folder path and slap them together.
        importPath = path.dirname(dirNamePath) + '/' + searchedImportPath + '.ts';
    }
}

And bam! You have a working Compodoc with route aliases.

[vogloblinsky]

Thanks for the PR