code: function eachApplicablePrefixPropertyMapping(prefixMapping, requestType, callback){
    Ember.keys(prefixMapping).forEach( (prefixName) => {
      let prefixPropertyMapping = prefixMapping[prefixName];
  
      let prefixPropName = prefixPropertyMapping.property;
      let conditions     = prefixPropertyMapping.only || [];
  
      if (checkConditions(requestType, conditions)) {
        callback(prefixName, prefixPropName);
      }
    });
  }
docs: Iterates through the items in the `prefixMapping` object and calls the callback for each prefixMapping that applies to this requestType. `requestType` is passed as the 4th argument to buildURL as of https://github.com/emberjs/data/commit/e8ceeeb4c099ab084a603c2b2564c56197c65fc5 We use the mixins/adapters/-lookup-methods-with-request-types mixin to add this `requestType` parameter until an ember-data version is released that has the requestType param.  The callback is called with (prefixName, prefixPropName).  The mapping can be an object with string keys and string values, or object values that specify which request types are applicable.  Example: { 'accounts': {property: 'stack.id', only:['create']} } This will result in prepending the string "/accounts/${record.get('stack.id')}" to create requests. `eachApplicablePrefixPropertyMapping` will invoke the callback once with ('accounts', 'stack.id') if the requestType matches 'create'.  See the model unit tests for more.