postprocess.md

postProcess built-in hook functions

fetchOne

Returns result if result is not an array, returns first element otherwise.

var fetchOne = require('koa-neo4j/postprocess').fetchOne;

app.defineAPI({
    // ..
    postProcess: fetchOne
    // ..
});

errorOnEmptyResult

Allows issuing an error if the result's length is zero, with the ability to specify an http error code. Default http error code for this hook function is 404.

var errorOnEmptyResult = require('koa-neo4j/postprocess').errorOnEmptyResult;

app.defineAPI({
    // ..
    postProcess: errorOnEmptyResult('query did not match any results', 500)
    // ..
});

map

Executes a function on each element of the result, gathers return values as the new result.

var map = require('koa-neo4j/postprocess').map;
var errorOnEmptyResult = require('koa-neo4j/postprocess').errorOnEmptyResult;

app.defineAPI({
    // ..
    postProcess: [
        errorOnEmptyResult('query did not match any results'),
        map(function(element) {
            return element.someValue;
        })
    ]
    // ..
});

convertToPreProcess

Converts a procedure to a preProcess hook function, result would be assigned to params.<key> where key is the name you've supplied as the argument to convertToPreProcess

var convertToPreProcess = require('koa-neo4j/postprocess').convertToPreProcess;
var parseIds = require('koa-neo4j/preprocess').parseIds;

var getAuthorId = app.createProcedure({
    // ...
    postProcess: [
        // ...
        // we need to provide the key
        convertToPreProcess('author_id'),
        // becomes params.author_id
        parseIds('author_id')
    ],
});

app.defineAPI({
    // ...
    preProcess: [
        // ...
        getAuthorId,
        function(params) {
            console.log(params.author_id);
            // logs result of getAuthorId
            return params;
        }
        // ...
    ],
    // ...
})