json-exec v0.2.1

json-exec

Fast templated json stringify. Convenient API, very simple to use. Great for logging, RPC, or other use cases where the object schema does not vary.

const json_comp = require('json-exec').json_comp;
const json_exec = require('json-exec').json_exec;

const coder = json_comp({ name: 'String', age: 123 });

json_exec({ name: 'Mickey Mouse', age: 91, color: 'black' });
// => '{"name":"Mickey Mouse","age":91}'
json_exec({ name: 'Minnie Mouse' });
// => '{"name":"Minnie Mouse","age":null}'

For example, to speed up the logging of fixed-pattern objects:

// auto-initialize the logline json encoder
var loglineCoder = loglineCoder || json_comp(logObject);
var logline = json_exec(loglineCoder, logObject);
logger.log(logline);

API

encoder = json_comp( templateObject )

Build a json encoder to stringify the properties of the template. The template is a duck-typing description of the properties and types to encode from data objects; in particular, the template may be an instance of a data object.

The data object properties should be of the same type as the corresponding template properties. A missing data property will be encoded as null (instead of being skipped as by JSON.stringify).

string = json_exec( encoder, dataObject )

Use the encoder to stringify the data object according to the template. Missing values are not skipped, they're stringified as null.

Changelog

• 0.1.0 - initial version with json_comp and json_exec

Todo

• allow for constant properties that will not be re-stringified each time
• build a template-specific stringifier function instead of walking the template

Related Work

• fast-json-stringify
• json-simple