/ / negative integer
re = /^-[0-9]+$/g
console.log("")
console.log("-1 test: true ", re.test(-1)) // true
console.log("-2 test: true ", re.test(-2)) // false
the second line output is: true
the third line output is: false
Why?
/ / negative integer
re = /^-[0-9]+$/g
console.log("")
console.log("-1 test: true ", re.test(-1)) // true
console.log("-2 test: true ", re.test(-2)) // false
the second line output is: true
the third line output is: false
Why?
because / g
remove g from the rule.
when using g , there is a lastIndex inside the regular time to record the last matching position. When the call is repeated, it will continue to match with the last lastIndex, which will lead to an error in judgment.
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