Introduction
Namaste, In this blog I will discuss 7 FAQs on Javascript fundamentals.
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Identify the output of the below program
let mydata = "ram" + false; console.log("mydata", mydata);a.error
b.ram0
c.ramfalse
d. truefalse
e.NaN
Answer:c
Reason: Here since one of the operands is a string and the + operator is used, the other operand will be coerced to string hence the output will be ramfalse.
Identify the output of the below program
let mydata= null+true; console.log("mydata", mydata);a.error
b.NaN
c.undefined
d. 1
e.0
Answer:d
Reason: Here null coerced into 0 and true to 1 hence the result is 1.
Identify the output of the below program
console.log("mydata", typeof break);a.error
b.NaN
c.undefined
d. string
e.null
Answer: a
Reason: It is a keyword hence cannot be used with typeof.
Identify the output of the below program
let mydata = null+null; console.log("mydata", mydata);a.error
b.NaN
c.true
d.0
e.1
Answer:d
Reason: Here null is coerced to 0 hence 0+0 is 0.
Identify the output of the below program
let mydata = null/false; console.log("mydata", mydata);a.NaN
b.0
c.1
d.error
e.undefined
Answer: a
Reason: Here null is coerced to the number which is 0 and false is coerced to the number which is 0 hence 0/0 in Javascript is NaN
Identify the output of the below program
let mydata=null+"ram";a.NaN
b.error
c.0ram
d. nullram
e.ramnull
Answer:d
Reason: Here since one of the operands is a string hence null is coerced to a string and concatenated with string therefore the result is nullram.
Identify the output of the below program
let mydata = true/null; console.log("mydata", mydata);a.NaN
b.Infinity
c.Error
d. 0
e.1
Answer:b
Reason: Here true is coerced to a number which is 1 and null is also coerced to a number which is 0 hence 1/0 in Javascript is Infinity.