jshape

jshape lets you shape any kind of value in JavaScript. It is ideal for mocking, validating, and fixing potentially unreliable data, which makes it both invaluable and unfortunate.

const { asShape } = require('jshape');

asShape('true', Boolean); // returns true
asShape(true, String); // returns 'true'
asShape('5', Number); // returns 5
asShape(
  { name: 'Amelia', age: '5' },
  { name: String, age: Number }
); // returns { name: 'Amelia', age: 5 }

jshape is 616 bytes when minified and gzipped.

Usage

Add jshape to your project:

npm install jshape --save

Use jshape to apply shapes to any value in JS:

const { asShape } = require('jshape');

const currentYear = new Date().getFullYear();

const example = {
  titles: {
    0: { title: 'Something A', isSomething: '1', year: '2018' },
    1: { title: 'Something B', isSomething: null, year: '2018' },
    2: { title: 'Something C', isSomething: null }
  }
};

asShape(example, {
  titles: [{
    title: String,
    isSomething: Boolean,
    year: currentYear
  }]
}); /* returns {
  titles: [
    { title: 'Something A', isSomething: true, year: 2018 },
    { title: 'Something B', isSomething: false, year: 2018 },
    { title: 'Something C', isSomething: false, year: currentYear }
  ]
} */

jshape runs in all Node environements and browsers including Internet Explorer 9+.

Test jshape in the browser:

<script src="https://unpkg.com/jshape/browser.js"></script>

Shapers

asShape

Returns any value as a specific kind of value determined by a shape.

const { asShape } = require('jshape');

asShape(value, shape, source);

• value: The value being guaranteed as a specific shape.
• shape: The function or value used to shape the value.
• source: The (optional) source being shaped, which is otherwise the value.

The source option is helpful when you want to create a new object, rather than mutate the original.

asShape Usage

const { asShape } = require('jshape');

asShape(objectNotBeingMutated, shape, { /* new object */ });

asArray

Returns any value as an array, conditionally preserving the original array.

const { asArray } = require('jshape');

asArray(value);

• value: The value being guaranteed as an array.

asArray Usage

const { asArray } = require('jshape');

asArray({ 0: 'foo', 1: 'bar' }); // returns ['foo', 'bar']

Primative Shapers

asBoolean

Returns any value as a primative boolean.

const { asBoolean } = require('jshape');

asBoolean(value);

• value: The value being guaranteed as a primative boolean.

asBoolean Usage

const { asBoolean } = require('jshape');

asBoolean('1'); // returns true
asBoolean(1); // returns true
asBoolean(0); // returns false
asBoolean(NaN); // returns false

asNumber

Returns any value as a primative number.

const { asNumber } = require('jshape');

asNumber(value);

• value: The value being guaranteed as a primative number.

asNumber Usage

const { asNumber } = require('jshape');

asNumber('1.337'); // returns 1.337
asNumber(true); // returns NaN

asString

Returns any value as a primative string.

const { asString } = require('jshape');

asString(value);

• value: The value being guaranteed as a primative string.

asString Usage

const { asString } = require('jshape');

asString(null); // returns ''
asString(0); // returns '0'
asString(false); // returns 'false'

Advanced Shaping

asHashmap

Returns a hashmap shape for inner element shaping.

const { asHashmap } = require('jshape');

asHashmap(shape);
asHashmap(shape, match);

• shape: The value being used to guarantee each element in the object hashmap.
• match: The (optional) pattern being used to shape hashmap keys.

asHashmap Usage

const { asShape, asHashmap } = require('jshape');

asShape({ '111': '1', '222': 2, 'ccc': 3 }, asHashmap(Number, /^\d+$/));
/* returns {
  '111': 1,
  '222': 2
} */

asOptional

Returns an optional shape for conditional shaping.

const { asOptional } = require('jshape');

asOptional(shape);

• shape: The value used to conditionally shape another value.

asOptional Usage

const { asShape, asOptional } = require('jshape');

asShape({ year: '2018' }, { year: asOptional(number) }) // returns { year: 2018 }
asShape({ year: null }, { year: asOptional(number) }) // returns { year: null }

How things are shapes

How Booleans are shaped

Booleans are shaped by the truthiness of a value. Values that are false, or omitted, or that are 0, -0, null, false, NaN, undefined, or an empty string return a Boolean primative of false. All other values, including any object or the string "false", return a Boolean primative of true.

const { asBoolean } = require('jshape');

asBoolean('1'); // returns true
asBoolean(1); // returns true
asBoolean(0); // returns false
asBoolean(NaN); // returns false

How Numbers are shaped

Numbers are shaped by numeric conversion. All values are returned as the numerified version of the value.

const { asNumber } = require('jshape');

asNumber('1.337'); // returns 1.337
asNumber(true); // returns NaN

How Strings are shaped

Strings are shaped by any identification. Values that are null or undefined are returned as an empty string, and all other values are returned as the stringified version of the value.

const { asString } = require('jshape');

asString(null); // returns ''
asString(0); // returns '0'
asString(false); // returns 'false'

How Arrays are shaped

Arrays are shaped by the iterableness of a value. Values that are Arrays are returned as-is. Values that are array-like objects with a length property return an Arrays of that length and their corresponding indexed elements. Values that are array-like objects with indexed elements and no length property are returned as Arrays with their length inferred by the length of the value's own property names. Values that are null or undefined return an empty Array, and all other values are returned as Array with one element which is the value.

How Hashmaps are shaped

Hashmaps are shaped by a shape and potentially a regular expression. Values are converted into objects, with keys omitted that do not match their optional regular expression.

const { asShape, asHashmap } = require('jshape');

asShape({ '111': '1', '222': 2, 'ccc': 3 }, asHashmap(Number));
/* returns {
  '111': 1,
  '222': 2
  'ccc': 3
} */

const { asShape, asHashmap } = require('jshape');

asShape({ '111': '1', '222': 2, 'ccc': 3 }, asHashmap(Number, /^\d+$/));
/* returns {
  '111': 1,
  '222': 2
} */