Module: core.inspect

Stability:3 - Stable
Bug Tracker:https://github.com/folktale/core.inspect/issues
Version:1.0.3
Repository:https://github.com/folktale/core.inspect
Portability:Portable
npm package:core.inspect 
Any → String

Human-readable representations for built-in and custom objects.

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Require the core.inspect package, after installing it:

var inspect = require('core.inspect')

The module itself is a specialised form of core.inspect.show() that has a limited maxDepth:

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inspect([1, [2, [3, [4, [5, [6]]]]]])
// => '[1, [2, [3, [4, [5, (...)]]]]]'

Why?

Some objects provide a custom representation, some do not. You usually want to see the custom textual representation if an object has it, since just showing its own properties might not give you enough information about it, or might not be as easy to read. But you also want to represent objects that don’t have a custom representation as something more useful than [object Object]. core.inspect solves this problem.

Consider a simple custom type representing a point in a 2d plane:

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function Point2d(x, y) {
  this.x = x;
  this.y = y;
}

Point2d.prototype.toString = function() {
  return 'Point2d(' + this.x + ', ' + this.y + ')'
}

If one wants to print a textual representation of this type, they’d call Point2d.toString():

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var p1 = new Point2d(10, 20);
p1.toString()
// => (String) "Point2d(10, 20)"

But what if you don’t know if the object you’re dealing with has a custom textual representation or not? In that case, you’d usually try to just display its properties:

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var Maybe = require('data.maybe');

var player = {
  lastPosition: Maybe.Nothing(),
  currentPosition: Maybe.Just(new Point2d(10, 20))
}

player

// => {
//      "lastPosition": {},
//      "currentPosition": {
//        "value": {
//          "x": 10,
//          "y": 20
//        }
//      }
//    }

In this example we have no way of knowing that lastPosition contains a Maybe.Nothing value, or that currentPosition is wrapped in a Maybe.Just. A more informative description would be what core.inspect gives you:

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var show = require('core.inspect');

show(player);
// => '{"lastPosition": Maybe.Nothing, "currentPosition": Maybe.Just(Point2d(10, 20))}'

Uncategorised

show()

core.inspect.show(maxDepth, value)
Returns:A human-readable representation of the value. 
Number → Any → String

Provides a human-readable representation of built-in values, and custom values implementing the ToString interface.