falcor-router

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Maybe this is just due to my own peculiar habits for implementing route handlers, or maybe this would be useful to everyone. I'll let you be the judge of that!

Anyhow, it would be nice to have built-in way to iterate every path in the pathSet passed to a route handler. For example something like this:

{
  route: 'users[{keys:ids}][{keys:props}]',
  async get(pathSet) {
    // pathSet is [ 'users', [ '123', '456' ], [ 'username', 'email' ] ]
    for (const path of pathSet.all()) { console.log(path); }
    // [ 'users', '123', 'username' ]
    // [ 'users', '123', 'email' ]
    // [ 'users', '456', 'username' ]
    // [ 'users', '456', 'email' ]
  }
}

Here's my implementation for example, which I've been using in all my route handlers.

export function* all(pathSet, pointer = 0, path = []) {
  if (pointer >= pathSet.length) {
    yield path.slice();
  } else {
    const thing = pathSet[pointer];
    for (const x of iterateThing(thing)) {
      path.push(x);
      yield* all(pathSet, pointer + 1, path);
      path.pop();
    }
  }
}

function* iterateThing(thing) {
  if (Array.isArray(thing)) {
    for (const subthing of thing) {
      yield* iterateThing(subthing);
    }
  } else if (isRange(thing)) {
    const { from, to } = thing;
    for (let i=from; i<=to; i++) {
      yield i;
    }
  } else {
    yield thing;
  }
}

function isRange(thing) {
  return thing && typeof thing.from === 'number';
}

Yes, that is essentially how the walkPath works as well. This could be useful. It would more than likely be put into the falcor-path-utils repo. Its useful.

Thanks for the response. I haven't looked much into falcor-path-utils, I'll have to check it out. Will it be attached as a method ala pathSet.all(), or is the idea for people to import falcor-path-utils and use it in their route handlers?

In the end pathSets are just Arrays of Arrays. So adding a method would be a bit yucky. But a utility method is where its at.