Do JavaScript line breaks need to be terminated with a semicolon?

JavaScript line breaks do not have to end with a semicolon; if each statement is written as a separate line, there is no need to end it with a semicolon, but if the next line encounters "(", "[", "/ ", " ", or "-", JavaScript may be combined with the next line for interpretation, so you need to use a semicolon to separate the two statements.

The operating environment of this tutorial: Windows 10 system, JavaScript version 1.8.5, Dell G3 computer.

Does JavaScript line break need to end with a semicolon?

About whether to add the last line of each code The semicolon problem

has such a characteristic: if a statement starts with "(", "[", "/", " ", or "-", then it is very likely to be combined with the previous statement. Explain together.

In other words, when writing javascript, if each statement is written on a separate line, there is no need to write a semicolon, but if the next line encounters the symbols mentioned above, javascript The explanation may be combined with the next line. In this case, a semicolon is needed to indicate that these are two statements.

See the following case for details:

Start with "("

a = b
(function(){
})()
//=============================================
//此时js会把上面的语句解释成：
a = b(function() {
})();

Starts with "["

a = function() {
 
}
[1,2,3].forEach(function(item) {
 
});
//=============================================
//此时js会把上面的语句解释成：
a = function() {
}[1,2,3].forEach(function(item) {
 
});

Starts with "/"

a = "abc"
/[a-z]/test(a)
//=============================================
//此时js会把上面的语句解释成：
a = "abc"/[a-z].text(a);

Starts with " " or "-"

a = b
 + c
//=============================================
 //js会把上面的语句解释成：
a = b + c;

a = b
- c
//=============================================
//此时js会把上面的语句解释成：
a = b - c;

In addition, if in return, break , continue, throw and other keywords, JavaScript will fill in the semicolon at the new line.

For example:

return 
{
a : 1
}
//=================================
//此时js会把上面的语句解释成：
return;
{
a : 1
}

If self-increment, self-decrement – ​​is used as the suffix of an expression, the expression It is best to write them on the same line, otherwise an error will be reported

as follows:

x
++
y
//上面的语句并不会被解释成
x++;
y;
//而会被解释成
1
2
x;
++y;

[Related recommendations: javascript video tutorial, web front-end]

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