Lodash – Number ”; Previous Next Lodash has many easy to use Number related methods. This chapter discusses them in detail. Lodash provides various Number related methods as listed below − Sr.No. Method & Syntax 1 clamp _.clamp(number, [lower], upper) 2 inRange _.inRange(number, [start=0], end) 3 random _.random([lower=0], [upper=1], [floating]) Print Page Previous Next Advertisements ”;
Lodash – Util ”; Previous Next Lodash has many easy to use Utility methods. This chapter discusses them in detail. Lodash provides various Utility methods as listed below − Sr.No. Method & Syntax 1 cond _.cond(pairs) 2 conforms _.conforms(source) 3 constant _.constant(value) 4 defaultTo _.defaultTo(value, defaultValue) 5 flow _.flow([funcs]) 6 flowRight _.flowRight([funcs]) 7 identity _.identity(value) 8 iteratee _.iteratee([func=_.identity]) 9 matches _.matches(source) 10 matchesProperty _.matchesProperty(path, srcValue) 11 method _.method(path, [args]) 12 methodOf _.methodOf(object, [args]) 13 mixin _.mixin([object=lodash], source, [options={}]) 14 noConflict _.noConflict() 15 noop _.noop() 16 nthArg _.nthArg([n=0]) 17 over _.over([iteratees=[_.identity]]) 18 overEvery _.overEvery([predicates=[_.identity]]) 19 overSome _.overSome([predicates=[_.identity]]) 20 property _.property(path) 21 propertyOf _.propertyOf(object) 22 range _.range([start=0], end, [step=1]) 23 rangeRight _.rangeRight([start=0], end, [step=1]) 24 runInContext _.runInContext([context=root]) 25 stubArray _.stubArray() 26 stubFalse _.stubFalse() 27 stubObject _.stubObject() 28 stubString _.stubString() 29 stubTrue _.stubTrue() 30 times _.times(n, [iteratee=_.identity]) 31 toPath _.toPath(value) 32 uniqueId _.uniqueId([prefix=””]) Print Page Previous Next Advertisements ”;
Lodash – Object ”; Previous Next Lodash has many easy to use Object related methods. This chapter discusses them in detail. Lodash provides various Object related methods as listed below − Sr.No. Method & Syntax 1 assign _.assign(object, [sources]) 2 assignIn _.assignIn(object, [sources]) 3 assignInWith _.assignInWith(object, sources, [customizer]) 4 assignWith _.assignWith(object, sources, [customizer]) 5 at _.at(object, [paths]) 6 create _.create(prototype, [properties]) 7 defaults _.defaults(object, [sources]) 8 defaultsDeep _.defaultsDeep(object, [sources]) 9 findKey _.findKey(object, [predicate=_.identity]) 10 findLastKey _.findLastKey(object, [predicate=_.identity]) 11 forIn _.forIn(object, [iteratee=_.identity]) 12 forInRight _.forInRight(object, [iteratee=_.identity]) 13 forOwn _.forOwn(object, [iteratee=_.identity]) 14 forOwnRight _.forOwnRight(object, [iteratee=_.identity]) 15 functions _.functions(object) 16 functionsIn _.functionsIn(object) 17 get _.get(object, path, [defaultValue]) 18 has _.has(object, path) 19 hasIn _.hasIn(object, path) 20 invert _.invert(object) 21 invertBy _.invertBy(object, [iteratee=_.identity]) 22 invoke _.invoke(object, path, [args]) 23 keys _.keys(object) 24 keysIn _.keysIn(object) 25 mapKeys _.mapKeys(object, [iteratee=_.identity]) 26 mapValues _.mapValues(object, [iteratee=_.identity]) 27 merge _.merge(object, [sources]) 28 mergeWith _.mergeWith(object, sources, customizer) 29 omit _.omit(object, [paths]) 30 omitBy _.omitBy(object, [predicate=_.identity]) 31 pick _.pick(object, [paths]) 32 pickBy _.pickBy(object, [predicate=_.identity]) 33 result _.result(object, path, [defaultValue]) 34 set _.set(object, path, value) 35 setWith _.setWith(object, path, value, [customizer]) 36 toPairs _.toPairs(object) 37 toPairsIn _.toPairsIn(object) 38 transform _.transform(object, [iteratee=_.identity], [accumulator]) 39 unset _.unset(object, path) 40 update _.update(object, path, updater) 41 updateWith _.updateWith(object, path, updater, [customizer]) 42 values _.values(object) 43 valuesIn _.valuesIn(object) Print Page Previous Next Advertisements ”;
Discuss Lodash ”; Previous Next Lodash is a popular javascript based library which provides 200+ functions to facilitate web development. It provides helper functions like map, filter, invoke as well as function binding, javascript templating, deep equality checks, creating indexes and so on. Lodash can be used directly inside a browser and also with Node.js. Working with objects using JavaScript can be quite challenging, specifically if you have lots of manipulation to be done with them. Underscore comes with lots of features that eases your work with objects. Print Page Previous Next Advertisements ”;
Lodash – Useful Resources ”; Previous Next The following resources contain additional information on Lodash. Please use them to get more in-depth knowledge on this. Useful Video Courses Node js for Course for beginners + Game project 27 Lectures 2.5 hours Laurence Svekis More Detail Functional Programming Course using JavaScript 52 Lectures 2 hours Skillbakery More Detail Ultimate JavaScript Arrays Course 43 Lectures 1 hours Daniel Stern More Detail Ultimate JavaScript Objects 66 Lectures 2 hours Daniel Stern More Detail Print Page Previous Next Advertisements ”;
Lodash – Methods ”; Previous Next This chapter discusses lodash properties in detail. Sr.No. Method & Syntax 1 _.VERSION − (string): The semantic version number. 2 _.templateSettings − (Object): By default, the template delimiters used by lodash are like those in embedded Ruby (ERB) as well as ES2015 template strings. Change the following template settings to use alternative delimiters. 3 _.templateSettings.escape − (RegExp): Used to detect data property values to be HTML-escaped. 4 _.templateSettings.evaluate − (RegExp): Used to detect code to be evaluated. 5 _.templateSettings.imports − (Object): Used to import variables into the compiled template. 6 _.templateSettings.interpolate − (RegExp): Used to detect data property values to inject. 7 _.templateSettings.variable − (string): Used to reference the data object in the template text. Print Page Previous Next Advertisements ”;
Lodash – Array ”; Previous Next Lodash has many easy to use methods which helps in processing Arrays. This chapter discusses them in detail. Lodash provides various methods to process the Arrays as listed below − Sr.No. Method & Syntax 1 chunk _.chunk(array, [size=1]) 2 compact _.compact(array) 3 concat _.concat(array, [values]) 4 difference _.difference(array, [values]) 5 differenceBy _.differenceBy(array, [values], [iteratee=_.identity]) 6 differenceWith _.differenceWith(array, [values], [comparator]) 7 drop _.drop(array, [n=1]) 8 dropRight _.dropRight(array, [n=1]) 9 dropRightWhile _.dropRightWhile(array, [predicate=_.identity]) 10 dropWhile _.dropWhile(array, [predicate=_.identity]) 11 fill _.fill(array, value, [start=0], [end=array.length]) 12 findIndex _.findIndex(array, [predicate=_.identity], [fromIndex=0]) 13 findLastIndex _.findLastIndex(array, [predicate=_.identity], [fromIndex=array.length-1]) 14 flatten _.flatten(array) 15 flattenDeep _.flattenDeep(array) 16 flattenDepth _.flattenDepth(array, [depth=1]) 17 fromPairs _.fromPairs(pairs) 18 head _.head(array) 19 indexOf _.indexOf(array, value, [fromIndex=0]) 20 initial _.initial(array) 21 intersection _.intersection([arrays]) 22 intersectionBy _.intersectionBy([arrays], [iteratee=_.identity]) 23 intersectionWith _.intersectionWith([arrays], [comparator]) 24 join _.join(array, [separator=”,”]) 25 last _.last(array) 26 lastIndexOf _.lastIndexOf(array, value, [fromIndex=array.length-1]) 27 nth _.nth(array, [n=0]) 28 pull _.pull(array, [values]) 29 pullAll _.pullAll(array, values) 30 pullAllBy _.pullAllBy(array, values, [iteratee=_.identity]) 31 pullAllWith _.pullAllWith(array, values, [comparator]) 32 pullAt _.pullAt(array, [indexes]) 33 remove _.remove(array, [predicate=_.identity]) 34 reverse _.reverse(array) 35 slice _.slice(array, [start=0], [end=array.length]) 36 sortedIndex _.sortedIndex(array, value) 37 sortedIndexBy _.sortedIndexBy(array, value, [iteratee=_.identity]) 38 sortedIndexOf _.sortedIndexOf(array, value) 39 sortedLastIndex _.sortedLastIndex(array, value) 40 sortedLastIndexBy _.sortedLastIndexBy(array, value, [iteratee=_.identity]) 41 sortedLastIndexOf _.sortedLastIndexOf(array, value) 42 sortedUniq _.sortedUniq(array) 43 sortedUniqBy _.sortedUniqBy(array, [iteratee]) 44 tail _.tail(array) 45 take _.take(array, [n=1]) 46 takeRight _.takeRight(array, [n=1]) 47 takeRightWhile _.takeRightWhile(array, [predicate=_.identity]) 48 takeWhile _.takeWhile(array, [predicate=_.identity]) 49 union _.union([arrays]) 50 unionBy _.unionBy([arrays], [iteratee=_.identity]) 51 unionWith _.unionWith([arrays], [comparator]) 52 uniq _.uniq(array) 53 uniqBy _.uniqBy(array, [iteratee=_.identity]) 54 uniqWith _.uniqWith(array, [comparator]) 55 unzip _.unzip(array) 56 unzipwith _.unzipWith(array, [iteratee=_.identity]) 57 without _.without(array, [values]) 58 xor _.xor([arrays]) 59 xorBy _.xorBy([arrays], [iteratee=_.identity]) 60 xorWith _.xorWith([arrays], [comparator]) 61 zip _.zip([arrays]) 62 zipObject _.zipObject([props=[]], [values=[]]) 63 zipObjectDeep _.zipObjectDeep([props=[]], [values=[]]) 64 zipWith _.zipWith([arrays], [iteratee=_.identity]) Print Page Previous Next Advertisements ”;
Lodash – Quick Guide ”; Previous Next Lodash – Overview Lodash is a popular javascript based library which provides 200+ functions to facilitate web development. It provides helper functions like map, filter, invoke as well as function binding, javascript templating, deep equality checks, creating indexes and so on. Lodash can be used directly inside a browser and also with Node.js. Working with objects using JavaScript can be quite challenging, specifically if you have lots of manipulation to be done with them. Lodash comes with lots of features that eases your work with objects. Lodash is an open source project and you can easily contribute to the library and add features in the form of plugins and make it available on GitHub and in Node.js. Features Let us understand in detail all the important features available with Lodash − Collections Lodash provides various functions for collections like each, map, reduce which are used to apply an operation on each item of a collection. It provides method like groupBy, countBy, max, min which processes collections and ease lot of tasks. Arrays Lodash provides various functions for arrays like to iterate and process arrays like first, initial, lastIndexOf, intersection, difference etc. Functions Lodash provides functions such as bind, delay, before, after etc. Objects Lodash provides functions to manipulate objects, to map objects and comparing objects. For example, keys, values, extends, extendsOwn, isEqual, isEmpty etc. Utilities Lodash provides various utilities methods like noConflict, random, iteratee, escape etc. Chaining Lodash provides chaining methods as well like chain, value. In subsequent chapters, we”ll cover important functions of Lodash Lodash – Environment Setup In this chapter, you will learn in detail about setting up the working environment of Lodash on your local computer. Before you begin with working on Lodash, you need to have the access to the library. You can access its files in any of the following methods − Method 1: Using Lodash File in Browser In this method, we are going to need Lodash file from its official website and will use it directly in the browser. Step 1 As a first step, go to the official website of Lodash https://lodash.com/. Observe that there is a download option available which gives you the latest lodash.min.js file CDN Copies available. Click on the link and select latest link for lodash.min.js. Step 2 Now, include lodash.min.js inside the script tag and start working with Lodash. For this, you can use the code given below − <script type = “text/JavaScript” src = “https://cdn.jsdelivr.net/npm/[email protected]/lodash.min.js”> </script> Given here is a working example and its output for a better understanding − Example <html> <head> <title>Lodash – Working Example</title> <script type = “text/JavaScript” src = “https://cdn.jsdelivr.net/npm/[email protected]/lodash.min.js”></script> <style> div { border: solid 1px #ccc; padding:10px; font-family: “Segoe UI”,Arial,sans-serif; width: 50%; } </style> </head> <body> <div style = “font-size:25px” id = “list”></div> <script type = “text/JavaScript”> var numbers = [1, 2, 3, 4]; var listOfNumbers = ””; _.each(numbers, function(x) { listOfNumbers += x + ” ” }); document.getElementById(“list”).innerHTML = listOfNumbers; </script> </body> </html> Output Method 2: Using Node.js If you are opting for this method, make sure you have Node.js and npm installed on your system. You can use the following command to install Lodash − npm install lodash You can observe the following output once Lodash is successfully installed − + [email protected] added 1 package from 2 contributors and audited 1 package in 2.54s found 0 vulnerabilities Now, to test if Lodash works fine with Node.js, create the file tester.js and add the following code to it − var _ = require(”lodash”); var numbers = [1, 2, 3, 4]; var listOfNumbers = ””; _.each(numbers, function(x) { listOfNumbers += x + ” ” }); console.log(listOfNumbers); Save the above program in tester.js. The following commands are used to compile and execute this program. Command >node tester.js Output 1 2 3 4 Lodash – Array Lodash has many easy to use methods which helps in processing Arrays. This chapter discusses them in detail. Lodash provides various methods to process the Arrays as listed below − Sr.No. Method & Syntax 1 chunk _.chunk(array, [size=1]) 2 compact _.compact(array) 3 concat _.concat(array, [values]) 4 difference _.difference(array, [values]) 5 differenceBy _.differenceBy(array, [values], [iteratee=_.identity]) 6 differenceWith _.differenceWith(array, [values], [comparator]) 7 drop _.drop(array, [n=1]) 8 dropRight _.dropRight(array, [n=1]) 9 dropRightWhile _.dropRightWhile(array, [predicate=_.identity]) 10 dropWhile _.dropWhile(array, [predicate=_.identity]) 11 fill _.fill(array, value, [start=0], [end=array.length]) 12 findIndex _.findIndex(array, [predicate=_.identity], [fromIndex=0]) 13 findLastIndex _.findLastIndex(array, [predicate=_.identity], [fromIndex=array.length-1]) 14 flatten _.flatten(array) 15 flattenDeep _.flattenDeep(array) 16 flattenDepth _.flattenDepth(array, [depth=1]) 17 fromPairs _.fromPairs(pairs) 18 head _.head(array) 19 indexOf _.indexOf(array, value, [fromIndex=0]) 20 initial _.initial(array) 21 intersection _.intersection([arrays]) 22 intersectionBy _.intersectionBy([arrays], [iteratee=_.identity]) 23 intersectionWith _.intersectionWith([arrays], [comparator]) 24 join _.join(array, [separator=”,”]) 25 last _.last(array) 26 lastIndexOf _.lastIndexOf(array, value, [fromIndex=array.length-1]) 27 nth _.nth(array, [n=0]) 28 pull _.pull(array, [values]) 29 pullAll
Lodash – Collection ”; Previous Next Lodash has many easy to use methods which helps in processing Collections. This chapter discusses them in detail. Lodash provides various methods to process the Collections as listed below − Sr.No. Method & Syntax 1 countBy _.countBy(collection, [iteratee=_.identity]) 2 every _.every(collection, [predicate=_.identity]) 3 filter _.filter(collection, [predicate=_.identity]) 4 find _.find(collection, [predicate=_.identity], [fromIndex=0]) 5 findLast _.findLast(collection, [predicate=_.identity], [fromIndex=collection.length-1]) 6 flatMap _.flatMap(collection, [iteratee=_.identity]) 7 flatMapDeep _.flatMapDeep(collection, [iteratee=_.identity]) 8 flatMapDepth _.flatMapDepth(collection, [iteratee=_.identity], [depth=1]) 9 forEach _.forEach(collection, [iteratee=_.identity]) 10 forEachRight _.forEachRight(collection, [iteratee=_.identity]) 11 groupBy _.groupBy(collection, [iteratee=_.identity]) 12 includes _.includes(collection, value, [fromIndex=0]) 13 invokeMap _.invokeMap(collection, path, [args]) 14 keyBy _.keyBy(collection, [iteratee=_.identity]) 15 map _.map(collection, [iteratee=_.identity]) 16 orderBy _.orderBy(collection, [iteratees=[_.identity]], [orders]) 17 partition _.partition(collection, [predicate=_.identity]) 18 reduce _.reduce(collection, [iteratee=_.identity], [accumulator]) 19 reduceRight _.reduceRight(collection, [iteratee=_.identity], [accumulator]) 20 reject _.reject(collection, [predicate=_.identity]) 21 sample _.sample(collection) 22 sampleSize _.sampleSize(collection, [n=1]) 23 shuffle _.shuffle(collection) 24 size _.size(collection) 25 some _.some(collection, [predicate=_.identity]) 26 sortBy _.sortBy(collection, [iteratees=[_.identity]]) Print Page Previous Next Advertisements ”;
Lodash – Properties ”; Previous Next This chapter discusses lodash properties in detail. Sr.No. Method & Syntax 1 _.VERSION − (string): The semantic version number. 2 _.templateSettings − (Object): By default, the template delimiters used by lodash are like those in embedded Ruby (ERB) as well as ES2015 template strings. Change the following template settings to use alternative delimiters. 3 _.templateSettings.escape − (RegExp): Used to detect data property values to be HTML-escaped. 4 _.templateSettings.evaluate − (RegExp): Used to detect code to be evaluated. 5 _.templateSettings.imports − (Object): Used to import variables into the compiled template. 6 _.templateSettings.interpolate − (RegExp): Used to detect data property values to inject. 7 _.templateSettings.variable − (string): Used to reference the data object in the template text. Print Page Previous Next Advertisements ”;