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samiul sheikh

samiul sheikh

Software Engineer

Ten important JavaScript Topics

3 min readMay 5, 2021

Today I discuss about Ten JavaScript basic topics. Hopefully that helps all JavaScript Developers.

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01. Variable (var, let, const)

For declare a variable we use var, let and const. var is not block level but let and const is block level variable. If we need to update a variable in later start the variable name using let. Other hand when we start a variable name using const that never be changed.

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02. Opertors

In JavaScript some numerical operator like +, -, *, /, %, =, ++, — etc.

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03. Object

In JavaScript access object property using (.) method or index method.

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04. String Slice method

Basically, slice method is using for divide a string to new piece of string and don’t change the original string. Let’s see with an example.

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05. String toLocaleLowerCase and toLocaleUpperCase method

toLocaleLowerCase method convert string into lowercase and toLocaleUpperCase method convert string into uppercase.

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06. NaN and parseInt method

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NaN means Not A Number. When we want to convert a string into number and if there is no number type then return NaN.

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07. toFixed method

Using toFixed method we can return long number into short number with specific digit. Below the example we convert four digits into two digits.

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08. Array Push method

Using array push method, we can add one or more elements in existing array. Below example we added new friend nadim into our friends array.

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Using push method with for loop

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09. Array pop method

Using array push method, we can remove last element from existing array. Below example we remove last element yellow from flowers array.

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10. Array Map method

Map method used to create new array using all elements from existing array. below example using map method we multiply all elements by 2.

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Thank you…

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samiul sheikh
samiul sheikh

Written by samiul sheikh

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Software Engineer