The difference in console.log output result: Why are the two calls different?

In-depth analysis of the output differences of console.log

This article analyzes the differences in the output results of the console.log function in a piece of code and explains the root cause. Code snippets involve different calling methods of URL parameter parsing and console.log , resulting in slight differences in output results.

The code first defines the getUrlParams function, which is used to parse URL parameters and returns an object containing all parameters. Then, the code calls getUrlParams to parse the sample URL and extracts the value of redirectKey parameter.

The key lies in the two different calls to console.log :

The first call: console.log(2, redirectKey); the output is 2 'bankList\n' .

The second call: console.log(redirectKey); the output result is bankList .

The root of the difference is that the value of redirectKey contains a newline character \n .

In the first call, multiple parameters are used, console.log outputs each parameter as a string and separates it with spaces. Therefore, \n is correctly displayed as an escape character \n instead of an actual line break.

In the second call, console.log only accepts one parameter, and it tries to output the string value of redirectKey directly. The browser interprets \n as a newline, causing \n itself not to appear, but instead produces an actual newline. Therefore, the second output looks like there is less \n , but \n still exists in the redirectKey variable, but the browser handles differently under different output methods.

After careful observation, the string output for the first time is enclosed in single quotes and contains \n ; the second time output is not displayed because the browser explains \n \n but the line break effect exists. On the surface, \n disappears, but in fact it still exists in the variable, and the way the browser handles it depends on how console.log is called.

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