sam-pattern/lib/sam-utils.js

SAM Pattern library

// ISC License (ISC)
// Copyright 2019 Jean-Jacques Dubray

// Permission to use, copy, modify, and/or distribute this software for any purpose
// with or without fee is hereby granted, provided that the above copyright notice
// and this permission notice appear in all copies.

// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
// OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
// OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
// ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.


// Optional chaining implementation
const O = (val, value = {}) => (val && (typeof val === 'object') ? val : value)
const A = (val, value = []) => (val && Array.isArray(val) ? val : value)
const S = (val, value = '') => (val && (typeof val === 'string') ? val : value)
const N = (val, value = 0) => (Number.isNaN(val) ? value : val)
const NZ = (val, value = 1) => (val === 0 || Number.isNaN(val) ? value === 0 ? 1 : value : val)
const F = (f, f0 = () => null) => (f || f0)

// Util functions often used in SAM implementations
const first = (arr = []) => arr[0]
const or = (acc, current) => acc || current
const and = (acc, current) => acc && current
const match = (conditions, values) => first(conditions.map((condition, index) => (condition ? values[index] : null)).filter(e))
const step = () => ({})
const doNotRender = model => () => model.continue() === true
const wrap = (s, w) => m => s(w(m))
const log = f => (...args) => {
  console.log(args)
  f(...args)
}
const e = value => (Array.isArray(value)
  ? value.map(e).reduce(and, true)
  : value === true || (value !== null && value !== undefined))

const i = (value, element) => {
  switch (typeof value) {
    case 'string': return typeof element === 'string' && value.includes(element)
    case 'object': return Array.isArray(value)
      ? value.includes(element)
      : typeof element === 'string' && e(value[element])
  }
  return value === element
}

const E = (value, element) => (e(value) && e(element)
  ? i(value, element)
  : e(value))

const oneOf = (value, f, guard = true) => {
  e(value) && guard && f(value)
  return mon(e(value))
}

const on = (value, f, guard = true) => {
  e(value) && guard && f(value)
  return { on }
}

const mon = (triggered = true) => ({
  oneOf: triggered ? () => mon() : oneOf
})

export {
  O, A, S, N, NZ, F, E, on, oneOf, or, and, match, step, doNotRender, first, wrap, log
}