Lodash 101

Lodash is one of the most popular utility-belt library. It can make you very productive and effective in writing Javascript programs.

Read Lodash's page on npm here. How many times was it downloaded just last week alone?

It was downloadeed 4,326,487 times.

Examples

Let's create a data array with the contents: 1,2,3,4,5. This array has 5 items.

To get the first item, we can use lodash's _.first.

return _.first(data)

The result is 1.

To get the first 3 elements, we can use lodash's _.take

return _.take(data, 3)

The result is 1,2,3.

Let's create a data array consisting of objects.

We can dump the content using the dump filter.

[{"name":"John","age":45},{"name":"Mary","age":32},{"name":"Peter","age":54}]

To retrieve the name field from each object in this array, lodash's _.pluck is very handy.

return _.pluck(data, 'name')

The result is John,Mary,Peter.

We can even display the result nicely as a bullet list

Using _.find, we can look up an object by its field.

Let's try to find out how old Mary is.

return _.find(data, {name: 'Mary'})

Mary is 32 years-old.

Now it's your turn to take the following learning challenges.

The data is

[{"name":"John","age":45},{"name":"Mary","age":32},{"name":"Peter","age":54},{"name":"Jane","age":12}]

ages = _.pluck(data, 'age')
return ages

The ages are 45,32,54,12

min_age = _.min(ages)
return min_age

The youngest age is 12.

return _.max(ages)

The oldest age is 54.

return _.find(data, {age: min_age})

The youngest person is Jane.