How to convert strings into objects and arrays in js_javascript skills

For example,

Copy code The code is as follows:

var test='{ colkey: "col", colsinfo: "NameList" }'

Obviously it is an object, but how to convert text into an object. When using eval(); be sure to add parentheses, otherwise the conversion will fail
Convert the text into an object

Copy code Code As follows:

var test='{ colkey: "col", colsinfo: "NameList" }'
var obj2=eval("(" test ")");
alert (obj2.colsinfo);

Convert text into array

Copy code The code is as follows:

var test='["colkey", "col", "colsinfo","NameList" ]'
var obj2=eval("(" test ")");
alert(obj2.length);