3条件(三元)运算符从右到左… ? … : … 2赋值从右到左… = … … += … … -= … … **= … … *= … … /= … … %= … … <<= … … >>= … … >>>= … … &= … … ^= … … |= … … &&= … … ||= … ...
When operators have the same precedence (like + and -), they are computed from left to right: letx =100/50*3; Try it Yourself » Operator Precedence Values Expressions in parentheses are computedbeforethe rest of the expression Function are executedbeforethe result is used in the rest of...
text ="x is defined"; } Try it Yourself » letx; if(typeofx ==="undefined") { text ="x is undefined"; }else{ text ="x is defined"; } Try it Yourself » More examples below. Description The undefined property indicates that a variable has not been assigned a value, or not...
The following table is ordered from highest (20) to lowest (0) precedence. PrecedenceOperator typeAssociativityIndividual operators 20Groupingn/a( … ) 19Member Accessleft-to-right… . … Computed Member Accessleft-to-right… [ … ] new(with argument list)n/anew … ( … ) ...
Operator precedencein JavaScript determines the priority of operators in an operation. It determines which operators have higher precedence than others, and thus tells us the order to perform a given mathematical expression. Operators with higher precedence will become the operands of operators with lowe...
15.8 When mixing operators, enclose them in parentheses. The only exception is the standard arithmetic operators: +, -, and ** since their precedence is broadly understood. We recommend enclosing / and * in parentheses because their precedence can be ambiguous when they are mixed. eslint: no-...
log('Yup.'); }; } Never name a parameter arguments. This will take precedence over the arguments object that is given to every function scope. // bad function nope(name, options, arguments) { // ...stuff... } // good function yup(name, options, args) { // ...stuff... }...
When new operators are added to JavaScript, they do not always fit naturally into this precedence scheme. The ?? operator (§4.13.2) is shown in the table as lower-precedence than || and &&, but, in fact, its precedence relative to those operators is not defined, and ES2020 requires ...
If you do this, be sure you are clear on the difference between the = and == operators! Note that = has very low precedence and parentheses are usually necessary when the value of an assignment is to be used in a larger expression. ...
Order of Precedence A regular expression is evaluated much like an arithmetic expression; that is, it is evaluated from left to right and follows an order of precedence. The following table contains the order of precedence of the regular expression operators, from highest to lowest. ...