Program :SourceElements SouceElements : SouceElement SouceElements SourceElement SouceElement...
The Else if statement is always used with the if statementand there can be as many else if statements as the program may require. Conditional statements uses various conditional and logical operators in order to compute the results. Use of Comparison and Logical Operators in Else If Statements T...
The most fundamental of the conditional statements is theifstatement. Anifstatement will evaluate whether a statement is true or false, and only run if the statement returnstrue. The code block will be ignored in the case of afalseresult, and the program will skip to the next section. Anif...
In addition toif...else, JavaScript has a feature known as aswitchstatement.switchis a type of conditional statement that will evaluate an expression against multiple possible cases and execute one or more blocks of code based on matching cases. Theswitchstatement is closely related to a conditio...
In the fol-lowing sections, you'll learn about the basic building blocks of JavaScript.05_0672328798_ch03.qxd 5/23/06 4:38 PM Page 3738HOUR 3:Getting Started with JavaScript ProgrammingStatementsStatements are the basic units of a JavaScript program. A statement is a section ofcode that ...
“Expected a conditional expression and instead saw an assignment.”:“此处需要一个表达式,而不是赋值语句”, “Expected a ‘break’ statement before ‘case’.”:“在’case’之前需要有’break’.”, “Expected a ‘break’ statement before ‘default’.”:“在’default’之前需要有’break’.”, ...
“Expected a conditional expression and instead saw an assignment.”:“此处需要一个表达式,而不是赋值语句”, “Expected a ‘break’ statement before ‘case’.”:“在’case’之前需要有’break’.”, “Expected a ‘break’ statement before ‘default’.”:“在’default’之前需要有’break’.”, ...
Roughly, astatementperforms an action.Loops andifstatements are examples of statements. A program is basically a sequence of statements.[8] Wherever JavaScript expects a statement,you can also write an expression. Such a statement is called anexpression statement. The reverse does not hold: you ...
代码里ast.program.body[0].declarations[0].id.name是 a 在 AST 中的位置,ast.program.body[0].declarations[0].init.value是 1 在 AST 中的位置,如下图所示: 08 @babel/traverse 当代码多了,我们不可能像前面那样挨个定位并修改,对于相同类型的节点,我们可以直接遍历所有节点来进行修改,这里就用到了@bab...
“Unexpected early end of program.”:“程序不可预期的提前终止”, “A leading decimal point can be confused with a dot: ‘.{a}’.”:“‘{a}’前的点容易混淆成小数点”, “Use the array literal notation [].”:“使用数组的符号 []“, ...