preprocess.md

preProcess built-in hook functions

parseWith

parseWith is a higher order function that takes a conversion method for one value as input and returns a preProcess hook function that takes arbitrary number of keys as argument and then goes deep in params, changing the value of each key to it's parsed value.

A key is either a string or an object mapping one string to another (parsed value would be assigned to keyToReplace in keys specified as {'keyToFind': 'keyToReplace'}).

var parseWith = require('koa-neo4j/preprocess').parseWith;
var neo4jInt = require('koa-neo4j/preprocess').neo4jInt;

// http://stackoverflow.com/questions/1494671/regular-expression-for-matching-time-in-military-24-hour-format
var parseMilitaryHour = parseWith(function(hourString) {
    return neo4jInt(/^([01]\d|2[0-3]):?([0-5]\d)$/.exec(hourString)[0]);
});

app.defineAPI({
    // ...
    preProcess: [
        parseIds('soldier_id', 'commander_id'),
        parseMilitaryHour(
            {'present_time': 'present_hour'},
            {'absent_time': 'absent_hour'}
        ),
        // ...
    ],
    // ...
});

built-in parse* methods are all derivatives of parseWith.

parseIds

Equivalent of parseNeo4jInts, renamed to be idiomatic.

parseNeo4jInts

Neo4j integer type is 64 bits and hence inconsistent with JavaScript's 53 bits integer type. This hook function parses a string or a JS integer into integer type consistent with neo4j.

Cypher only works with integers of type Neo4j integer.

parseUnixTimes

Converts a UnixTime string or integer to a Neo4jInt, making it ready for Cypher to work with.

parseDates

Converts a string or UnixTime into a JavaScript Date object.

parseInts

Parses keys as JavaScript integer values.

parseFloats

Parses keys as JavaScript float values.