In the last article, we talked about how to convert numeric types. Today, we will summarize the methods of converting strings and Boolean types:
The main methods of converting strings are:
toString();
String();
The specific usage is shown in the following table:
| method | example | return value | illustrate |
|---|---|---|---|
| toString(): undefined and null have no toString() method |
['1','2','3'].toString() | 1,2,3 | Convert the elements of the Array to strings. The resulting strings are comma-separated and concatenated. |
| true.toString() | "true" | Returns "true" if the Boolean value is true. Otherwise, return "false". | |
| var num = 111; console.log(num.toString()); |
"111" | Convert number type to string type | |
| String() | String() can convert null and undefined to strings, but not to strings. String(null), returns "null". String(undefined), returns "undefined". |
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The main methods of converting Boolean types are:
Boolean()：
The specific usage is shown in the following table:
| method | example | return value | illustrate |
|---|---|---|---|
| Boolean(): Converts any type of value to a boolean |
Boolean(false) | false | false, "", 0, NaN, null, undefined, and any other values are converted to true. |
| Boolean("") | false | ||
| Boolean(0) | false | ||
| Boolean (NaN) | false | ||
| Boolean(undefined) | false | ||
| Boolean("false") | true | ||
| Convert "false" of type string to false of type Boolean: var value = "false"; var flag = value ==="false" ? false : true; |
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