wrapperLodash

Creates a lodash object which wraps value to enable implicit method chain sequences. Methods that operate on and return arrays, collections, and functions can be chained together. Methods that retrieve a single value or may return a primitive value will automatically end the chain sequence and return the unwrapped value. Otherwise, the value must be unwrapped with _#value.

Explicit chain sequences, which must be unwrapped with _#value, may be enabled using _.chain.

The execution of chained methods is lazy, that is, it's deferred until _#value is implicitly or explicitly called.

Lazy evaluation allows several methods to support shortcut fusion. Shortcut fusion is an optimization to merge iteratee calls; this avoids the creation of intermediate arrays and can greatly reduce the number of iteratee executions. Sections of a chain sequence qualify for shortcut fusion if the section is applied to an array and iteratees accept only one argument. The heuristic for whether a section qualifies for shortcut fusion is subject to change.

Chaining is supported in custom builds as long as the _#value method is directly or indirectly included in the build.

In addition to lodash methods, wrappers have Array and String methods.

The wrapper Array methods are: concat, join, pop, push, shift, sort, splice, and unshift

The wrapper String methods are: replace and split

The wrapper methods that support shortcut fusion are: at, compact, drop, dropRight, dropWhile, filter, find, findLast, head, initial, last, map, reject, reverse, slice, tail, take, takeRight, takeRightWhile, takeWhile, and toArray

The chainable wrapper methods are: after, ary, assign, assignIn, assignInWith, assignWith, at, before, bind, bindAll, bindKey, castArray, chain, chunk, commit, compact, concat, conforms, constant, countBy, create, curry, debounce, defaults, defaultsDeep, defer, delay, difference, differenceBy, differenceWith, drop, dropRight, dropRightWhile, dropWhile, extend, extendWith, fill, filter, flatMap, flatMapDeep, flatMapDepth, flatten, flattenDeep, flattenDepth, flip, flow, flowRight, fromPairs, functions, functionsIn, groupBy, initial, intersection, intersectionBy, intersectionWith, invert, invertBy, invokeMap, iteratee, keyBy, keys, keysIn, map, mapKeys, mapValues, matches, matchesProperty, memoize, merge, mergeWith, method, methodOf, mixin, negate, nthArg, omit, omitBy, once, orderBy, over, overArgs, overEvery, overSome, partial, partialRight, partition, pick, pickBy, plant, property, propertyOf, pull, pullAll, pullAllBy, pullAllWith, pullAt, push, range, rangeRight, rearg, reject, remove, rest, reverse, sampleSize, set, setWith, shuffle, slice, sort, sortBy, splice, spread, tail, take, takeRight, takeRightWhile, takeWhile, tap, throttle, thru, toArray, toPairs, toPairsIn, toPath, toPlainObject, transform, unary, union, unionBy, unionWith, uniq, uniqBy, uniqWith, unset, unshift, unzip, unzipWith, update, updateWith, values, valuesIn, without, wrap, xor, xorBy, xorWith, zip, zipObject, zipObjectDeep, and zipWith

The wrapper methods that are not chainable by default are: add, attempt, camelCase, capitalize, ceil, clamp, clone, cloneDeep, cloneDeepWith, cloneWith, conformsTo, deburr, defaultTo, divide, each, eachRight, endsWith, eq, escape, escapeRegExp, every, find, findIndex, findKey, findLast, findLastIndex, findLastKey, first, floor, forEach, forEachRight, forIn, forInRight, forOwn, forOwnRight, get, gt, gte, has, hasIn, head, identity, includes, indexOf, inRange, invoke, isArguments, isArray, isArrayBuffer, isArrayLike, isArrayLikeObject, isBoolean, isBuffer, isDate, isElement, isEmpty, isEqual, isEqualWith, isError, isFinite, isFunction, isInteger, isLength, isMap, isMatch, isMatchWith, isNaN, isNative, isNil, isNull, isNumber, isObject, isObjectLike, isPlainObject, isRegExp, isSafeInteger, isSet, isString, isUndefined, isTypedArray, isWeakMap, isWeakSet, join, kebabCase, last, lastIndexOf, lowerCase, lowerFirst, lt, lte, max, maxBy, mean, meanBy, min, minBy, multiply, noConflict, noop, now, nth, pad, padEnd, padStart, parseInt, pop, random, reduce, reduceRight, repeat, result, round, runInContext, sample, shift, size, snakeCase, some, sortedIndex, sortedIndexBy, sortedLastIndex, sortedLastIndexBy, startCase, startsWith, stubArray, stubFalse, stubObject, stubString, stubTrue, subtract, sum, sumBy, template, times, toFinite, toInteger, toJSON, toLength, toLower, toNumber, toSafeInteger, toString, toUpper, trim, trimEnd, trimStart, truncate, unescape, uniqueId, upperCase, upperFirst, value, and words

function square(n) {
  return n * n;
}

var wrapped = _([1, 2, 3]);

// Returns an unwrapped value.
wrapped.reduce(_.add);
// => 6

// Returns a wrapped value.
var squares = wrapped.map(square);

_.isArray(squares);
// => false

_.isArray(squares.value());
// => true