WeChat small program statement

The if statement

In WXS, you can use if statements in the following format:

• if (expression) statement: When expression is true, the statement is executed.
• if (expression) statement1 else statement2: When expression is true, statement1 is executed. Otherwise, statement2 is executed
• if ... e lse if ... Else statementN allows you to select one of the executions between statement1 and statementN.

Example syntax:

// if ...

if (表达式) 语句;

if (表达式) 
  语句;

if (表达式) {
  代码块;
}


// if ... else 

if (表达式) 语句;
else 语句;

if (表达式) 
  语句;
else 
  语句;

if (表达式) {
  代码块;
} else {
  代码块;
}

// if ... else if ... else ...

if (表达式) {
  代码块;
} else if (表达式) {
  代码块;
} else if (表达式) {
  代码块;
} else {
  代码块;
}

Switch statement

Example syntax:

switch (表达式) {
  case 变量:
    语句;
  case 数字:
    语句;
    break;
  case 字符串:
    语句;
  default:
    语句;
}

• The default branch can be omitted from writing.
• Case keywords can only be used after: variables, numbers, strings.

Example code:

var exp = 10;

switch ( exp ) {
case "10":
  console.log("string 10");
  break;
case 10:
  console.log("number 10");
  break;
case exp:
  console.log("var exp");
  break;
default:
  console.log("default");
}

Output:

number 10

The for statement

Example syntax:

for (语句; 语句; 语句)
  语句;

for (语句; 语句; 语句) {
  代码块;
}

• Supports the use of break, continue keywords.

Example code:

for (var i = 0; i < 3; ++i) {
  console.log(i);
  if( i >= 1) break;
}

Output:

0
1

While statement

Example syntax:

while (表达式)
  语句;

while (表达式){
  代码块;
}

do {
  代码块;
} while (表达式)

• When the expression is true, the loop executes a statement or block of code.
• Supports the use of break, continue keywords.