simple-squiggle

array.js (16053B)

---

 import { isInteger } from './number.js';
 import { isNumber } from './is.js';
 import { format } from './string.js';
 import { DimensionError } from '../error/DimensionError.js';
 import { IndexError } from '../error/IndexError.js';
 /**
  * Calculate the size of a multi dimensional array.
  * This function checks the size of the first entry, it does not validate
  * whether all dimensions match. (use function `validate` for that)
  * @param {Array} x
  * @Return {Number[]} size
  */
 
 export function arraySize(x) {
   var s = [];
 
   while (Array.isArray(x)) {
     s.push(x.length);
     x = x[0];
   }
 
   return s;
 }
 /**
  * Recursively validate whether each element in a multi dimensional array
  * has a size corresponding to the provided size array.
  * @param {Array} array    Array to be validated
  * @param {number[]} size  Array with the size of each dimension
  * @param {number} dim   Current dimension
  * @throws DimensionError
  * @private
  */
 
 function _validate(array, size, dim) {
   var i;
   var len = array.length;
 
   if (len !== size[dim]) {
     throw new DimensionError(len, size[dim]);
   }
 
   if (dim < size.length - 1) {
     // recursively validate each child array
     var dimNext = dim + 1;
 
     for (i = 0; i < len; i++) {
       var child = array[i];
 
       if (!Array.isArray(child)) {
         throw new DimensionError(size.length - 1, size.length, '<');
       }
 
       _validate(array[i], size, dimNext);
     }
   } else {
     // last dimension. none of the childs may be an array
     for (i = 0; i < len; i++) {
       if (Array.isArray(array[i])) {
         throw new DimensionError(size.length + 1, size.length, '>');
       }
     }
   }
 }
 /**
  * Validate whether each element in a multi dimensional array has
  * a size corresponding to the provided size array.
  * @param {Array} array    Array to be validated
  * @param {number[]} size  Array with the size of each dimension
  * @throws DimensionError
  */
 
 
 export function validate(array, size) {
   var isScalar = size.length === 0;
 
   if (isScalar) {
     // scalar
     if (Array.isArray(array)) {
       throw new DimensionError(array.length, 0);
     }
   } else {
     // array
     _validate(array, size, 0);
   }
 }
 /**
  * Test whether index is an integer number with index >= 0 and index < length
  * when length is provided
  * @param {number} index    Zero-based index
  * @param {number} [length] Length of the array
  */
 
 export function validateIndex(index, length) {
   if (!isNumber(index) || !isInteger(index)) {
     throw new TypeError('Index must be an integer (value: ' + index + ')');
   }
 
   if (index < 0 || typeof length === 'number' && index >= length) {
     throw new IndexError(index, length);
   }
 }
 /**
  * Resize a multi dimensional array. The resized array is returned.
  * @param {Array} array         Array to be resized
  * @param {Array.<number>} size Array with the size of each dimension
  * @param {*} [defaultValue=0]  Value to be filled in in new entries,
  *                              zero by default. Specify for example `null`,
  *                              to clearly see entries that are not explicitly
  *                              set.
  * @return {Array} array         The resized array
  */
 
 export function resize(array, size, defaultValue) {
   // TODO: add support for scalars, having size=[] ?
   // check the type of the arguments
   if (!Array.isArray(array) || !Array.isArray(size)) {
     throw new TypeError('Array expected');
   }
 
   if (size.length === 0) {
     throw new Error('Resizing to scalar is not supported');
   } // check whether size contains positive integers
 
 
   size.forEach(function (value) {
     if (!isNumber(value) || !isInteger(value) || value < 0) {
       throw new TypeError('Invalid size, must contain positive integers ' + '(size: ' + format(size) + ')');
     }
   }); // recursively resize the array
 
   var _defaultValue = defaultValue !== undefined ? defaultValue : 0;
 
   _resize(array, size, 0, _defaultValue);
 
   return array;
 }
 /**
  * Recursively resize a multi dimensional array
  * @param {Array} array         Array to be resized
  * @param {number[]} size       Array with the size of each dimension
  * @param {number} dim          Current dimension
  * @param {*} [defaultValue]    Value to be filled in in new entries,
  *                              undefined by default.
  * @private
  */
 
 function _resize(array, size, dim, defaultValue) {
   var i;
   var elem;
   var oldLen = array.length;
   var newLen = size[dim];
   var minLen = Math.min(oldLen, newLen); // apply new length
 
   array.length = newLen;
 
   if (dim < size.length - 1) {
     // non-last dimension
     var dimNext = dim + 1; // resize existing child arrays
 
     for (i = 0; i < minLen; i++) {
       // resize child array
       elem = array[i];
 
       if (!Array.isArray(elem)) {
         elem = [elem]; // add a dimension
 
         array[i] = elem;
       }
 
       _resize(elem, size, dimNext, defaultValue);
     } // create new child arrays
 
 
     for (i = minLen; i < newLen; i++) {
       // get child array
       elem = [];
       array[i] = elem; // resize new child array
 
       _resize(elem, size, dimNext, defaultValue);
     }
   } else {
     // last dimension
     // remove dimensions of existing values
     for (i = 0; i < minLen; i++) {
       while (Array.isArray(array[i])) {
         array[i] = array[i][0];
       }
     } // fill new elements with the default value
 
 
     for (i = minLen; i < newLen; i++) {
       array[i] = defaultValue;
     }
   }
 }
 /**
  * Re-shape a multi dimensional array to fit the specified dimensions
  * @param {Array} array           Array to be reshaped
  * @param {Array.<number>} sizes  List of sizes for each dimension
  * @returns {Array}               Array whose data has been formatted to fit the
  *                                specified dimensions
  *
  * @throws {DimensionError}       If the product of the new dimension sizes does
  *                                not equal that of the old ones
  */
 
 
 export function reshape(array, sizes) {
   var flatArray = flatten(array);
   var currentLength = flatArray.length;
 
   if (!Array.isArray(array) || !Array.isArray(sizes)) {
     throw new TypeError('Array expected');
   }
 
   if (sizes.length === 0) {
     throw new DimensionError(0, currentLength, '!=');
   }
 
   sizes = processSizesWildcard(sizes, currentLength);
   var newLength = product(sizes);
 
   if (currentLength !== newLength) {
     throw new DimensionError(newLength, currentLength, '!=');
   }
 
   try {
     return _reshape(flatArray, sizes);
   } catch (e) {
     if (e instanceof DimensionError) {
       throw new DimensionError(newLength, currentLength, '!=');
     }
 
     throw e;
   }
 }
 /**
  * Replaces the wildcard -1 in the sizes array.
  * @param {Array.<number>} sizes  List of sizes for each dimension. At most on wildcard.
  * @param {number} currentLength  Number of elements in the array.
  * @throws {Error}                If more than one wildcard or unable to replace it.
  * @returns {Array.<number>}      The sizes array with wildcard replaced.
  */
 
 export function processSizesWildcard(sizes, currentLength) {
   var newLength = product(sizes);
   var processedSizes = sizes.slice();
   var WILDCARD = -1;
   var wildCardIndex = sizes.indexOf(WILDCARD);
   var isMoreThanOneWildcard = sizes.indexOf(WILDCARD, wildCardIndex + 1) >= 0;
 
   if (isMoreThanOneWildcard) {
     throw new Error('More than one wildcard in sizes');
   }
 
   var hasWildcard = wildCardIndex >= 0;
   var canReplaceWildcard = currentLength % newLength === 0;
 
   if (hasWildcard) {
     if (canReplaceWildcard) {
       processedSizes[wildCardIndex] = -currentLength / newLength;
     } else {
       throw new Error('Could not replace wildcard, since ' + currentLength + ' is no multiple of ' + -newLength);
     }
   }
 
   return processedSizes;
 }
 /**
  * Computes the product of all array elements.
  * @param {Array<number>} array Array of factors
  * @returns {number}            Product of all elements
  */
 
 function product(array) {
   return array.reduce((prev, curr) => prev * curr, 1);
 }
 /**
  * Iteratively re-shape a multi dimensional array to fit the specified dimensions
  * @param {Array} array           Array to be reshaped
  * @param {Array.<number>} sizes  List of sizes for each dimension
  * @returns {Array}               Array whose data has been formatted to fit the
  *                                specified dimensions
  */
 
 
 function _reshape(array, sizes) {
   // testing if there are enough elements for the requested shape
   var tmpArray = array;
   var tmpArray2; // for each dimensions starting by the last one and ignoring the first one
 
   for (var sizeIndex = sizes.length - 1; sizeIndex > 0; sizeIndex--) {
     var size = sizes[sizeIndex];
     tmpArray2 = []; // aggregate the elements of the current tmpArray in elements of the requested size
 
     var length = tmpArray.length / size;
 
     for (var i = 0; i < length; i++) {
       tmpArray2.push(tmpArray.slice(i * size, (i + 1) * size));
     } // set it as the new tmpArray for the next loop turn or for return
 
 
     tmpArray = tmpArray2;
   }
 
   return tmpArray;
 }
 /**
  * Squeeze a multi dimensional array
  * @param {Array} array
  * @param {Array} [size]
  * @returns {Array} returns the array itself
  */
 
 
 export function squeeze(array, size) {
   var s = size || arraySize(array); // squeeze outer dimensions
 
   while (Array.isArray(array) && array.length === 1) {
     array = array[0];
     s.shift();
   } // find the first dimension to be squeezed
 
 
   var dims = s.length;
 
   while (s[dims - 1] === 1) {
     dims--;
   } // squeeze inner dimensions
 
 
   if (dims < s.length) {
     array = _squeeze(array, dims, 0);
     s.length = dims;
   }
 
   return array;
 }
 /**
  * Recursively squeeze a multi dimensional array
  * @param {Array} array
  * @param {number} dims Required number of dimensions
  * @param {number} dim  Current dimension
  * @returns {Array | *} Returns the squeezed array
  * @private
  */
 
 function _squeeze(array, dims, dim) {
   var i, ii;
 
   if (dim < dims) {
     var next = dim + 1;
 
     for (i = 0, ii = array.length; i < ii; i++) {
       array[i] = _squeeze(array[i], dims, next);
     }
   } else {
     while (Array.isArray(array)) {
       array = array[0];
     }
   }
 
   return array;
 }
 /**
  * Unsqueeze a multi dimensional array: add dimensions when missing
  *
  * Paramter `size` will be mutated to match the new, unqueezed matrix size.
  *
  * @param {Array} array
  * @param {number} dims       Desired number of dimensions of the array
  * @param {number} [outer]    Number of outer dimensions to be added
  * @param {Array} [size] Current size of array.
  * @returns {Array} returns the array itself
  * @private
  */
 
 
 export function unsqueeze(array, dims, outer, size) {
   var s = size || arraySize(array); // unsqueeze outer dimensions
 
   if (outer) {
     for (var i = 0; i < outer; i++) {
       array = [array];
       s.unshift(1);
     }
   } // unsqueeze inner dimensions
 
 
   array = _unsqueeze(array, dims, 0);
 
   while (s.length < dims) {
     s.push(1);
   }
 
   return array;
 }
 /**
  * Recursively unsqueeze a multi dimensional array
  * @param {Array} array
  * @param {number} dims Required number of dimensions
  * @param {number} dim  Current dimension
  * @returns {Array | *} Returns the squeezed array
  * @private
  */
 
 function _unsqueeze(array, dims, dim) {
   var i, ii;
 
   if (Array.isArray(array)) {
     var next = dim + 1;
 
     for (i = 0, ii = array.length; i < ii; i++) {
       array[i] = _unsqueeze(array[i], dims, next);
     }
   } else {
     for (var d = dim; d < dims; d++) {
       array = [array];
     }
   }
 
   return array;
 }
 /**
  * Flatten a multi dimensional array, put all elements in a one dimensional
  * array
  * @param {Array} array   A multi dimensional array
  * @return {Array}        The flattened array (1 dimensional)
  */
 
 
 export function flatten(array) {
   if (!Array.isArray(array)) {
     // if not an array, return as is
     return array;
   }
 
   var flat = [];
   array.forEach(function callback(value) {
     if (Array.isArray(value)) {
       value.forEach(callback); // traverse through sub-arrays recursively
     } else {
       flat.push(value);
     }
   });
   return flat;
 }
 /**
  * A safe map
  * @param {Array} array
  * @param {function} callback
  */
 
 export function map(array, callback) {
   return Array.prototype.map.call(array, callback);
 }
 /**
  * A safe forEach
  * @param {Array} array
  * @param {function} callback
  */
 
 export function forEach(array, callback) {
   Array.prototype.forEach.call(array, callback);
 }
 /**
  * A safe filter
  * @param {Array} array
  * @param {function} callback
  */
 
 export function filter(array, callback) {
   if (arraySize(array).length !== 1) {
     throw new Error('Only one dimensional matrices supported');
   }
 
   return Array.prototype.filter.call(array, callback);
 }
 /**
  * Filter values in a callback given a regular expression
  * @param {Array} array
  * @param {RegExp} regexp
  * @return {Array} Returns the filtered array
  * @private
  */
 
 export function filterRegExp(array, regexp) {
   if (arraySize(array).length !== 1) {
     throw new Error('Only one dimensional matrices supported');
   }
 
   return Array.prototype.filter.call(array, entry => regexp.test(entry));
 }
 /**
  * A safe join
  * @param {Array} array
  * @param {string} separator
  */
 
 export function join(array, separator) {
   return Array.prototype.join.call(array, separator);
 }
 /**
  * Assign a numeric identifier to every element of a sorted array
  * @param {Array} a  An array
  * @return {Array} An array of objects containing the original value and its identifier
  */
 
 export function identify(a) {
   if (!Array.isArray(a)) {
     throw new TypeError('Array input expected');
   }
 
   if (a.length === 0) {
     return a;
   }
 
   var b = [];
   var count = 0;
   b[0] = {
     value: a[0],
     identifier: 0
   };
 
   for (var i = 1; i < a.length; i++) {
     if (a[i] === a[i - 1]) {
       count++;
     } else {
       count = 0;
     }
 
     b.push({
       value: a[i],
       identifier: count
     });
   }
 
   return b;
 }
 /**
  * Remove the numeric identifier from the elements
  * @param {array} a  An array
  * @return {array} An array of values without identifiers
  */
 
 export function generalize(a) {
   if (!Array.isArray(a)) {
     throw new TypeError('Array input expected');
   }
 
   if (a.length === 0) {
     return a;
   }
 
   var b = [];
 
   for (var i = 0; i < a.length; i++) {
     b.push(a[i].value);
   }
 
   return b;
 }
 /**
  * Check the datatype of a given object
  * This is a low level implementation that should only be used by
  * parent Matrix classes such as SparseMatrix or DenseMatrix
  * This method does not validate Array Matrix shape
  * @param {Array} array
  * @param {function} typeOf   Callback function to use to determine the type of a value
  * @return {string}
  */
 
 export function getArrayDataType(array, typeOf) {
   var type; // to hold type info
 
   var length = 0; // to hold length value to ensure it has consistent sizes
 
   for (var i = 0; i < array.length; i++) {
     var item = array[i];
     var isArray = Array.isArray(item); // Saving the target matrix row size
 
     if (i === 0 && isArray) {
       length = item.length;
     } // If the current item is an array but the length does not equal the targetVectorSize
 
 
     if (isArray && item.length !== length) {
       return undefined;
     }
 
     var itemType = isArray ? getArrayDataType(item, typeOf) // recurse into a nested array
     : typeOf(item);
 
     if (type === undefined) {
       type = itemType; // first item
     } else if (type !== itemType) {
       return 'mixed';
     } else {// we're good, everything has the same type so far
     }
   }
 
   return type;
 }
 /**
  * Return the last item from an array
  * @param array
  * @returns {*}
  */
 
 export function last(array) {
   return array[array.length - 1];
 }
 /**
  * Get all but the last element of array.
  */
 
 export function initial(array) {
   return array.slice(0, array.length - 1);
 }
 /**
  * Test whether an array or string contains an item
  * @param {Array | string} array
  * @param {*} item
  * @return {boolean}
  */
 
 export function contains(array, item) {
   return array.indexOf(item) !== -1;
 }