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get caller filename, and line number. to use for debug, and testing.
npm install --save git+https://github.com/taku-o/caller-position#master
As a node module:
var caller = require('caller-position');
console.log(caller.caller());
console.log(caller.position());
returning value example are,
{ filename_base: 'test.js', line_no: '3', line_pos: '20' }
test.js:3