moltres-utils/dist/common/nArySpread.js

Utils for Moltres apps

"use strict";

require("core-js/modules/es6.object.define-property");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;

var _curry = _interopRequireDefault(require("./curry"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * Wraps a function of any arity (including nullary) in a function that accepts exactly `n` parameters. Any extraneous parameters are spread and then reapplied on execution. This is useful when you want to ensure a function's paramter length is exactly `n` but still passes all arguments through.
 *
 * @function
 * @since v0.0.4
 * @category common
 * @param {Number} n The desired arity of the new function.
 * @param {Function} fn The function to wrap.
 * @returns {Function} A new function wrapping `fn`. The new function is guaranteed to be of parameter length `n`.
 * @example
 *
 * const takesNArgs = (...args) => [ ...args ]
 *
 * takesNArgs.length //=> 0
 * takesNArgs(1, 2) //=> [1, 2]
 *
 * const takesTwoArgs = nArySpread(2, takesNArgs)
 * takesTwoArgs.length //=> 2
 * // All arguments are passed to the wrapped function
 * takesTwoArgs(1, 2, 3) //=> [1, 2, 3]
 *
 * const curriedTakesTwoArgs = curry(takesTwoArgs)
 * // auto currying works as expected
 * const takesAtLeastOneMoreArg = curriedTakesTwoArgs(3)
 * takesAtLeastOneMoreArg(1, 2) // => [3, 1, 2]
 */
var nArySpread = (0, _curry.default)(function (n, fn) {
  var idx = 0;
  var argNames = [];

  while (idx < n) {
    argNames.push("a".concat(idx));
    idx += 1;
  }

  var func = new Function('fn', "return function(".concat(argNames.join(', '), ") {\n      return fn.apply(this, arguments);\n    }"));
  return func(fn);
});
var _default = nArySpread;
exports.default = _default;
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