Node.js unset environment variable

Another way to clear a local environment variable is by using unset command (Linux/Mac). To unset any local environment variable temporarily:\n$ unset <var-name>\n\nwhere <var-name> is the name of local variable which you want to unset or clear.",

There is another unintuitive aspect to it: Node.js converts undefined to the string "undefined" when assigning an environment variable:\n> process.env.MYVAR = undefined\nundefined\n> typeof process.env.MYVAR\n'string'\n\nYou can work around this using delete:\n> delete process.env.MYVAR\ntrue\n> typeof process.env.MYVAR\n'undefined'\n\nTested with Node.js 10.18, 12.14, 13.5 and 16.15.\nFor this reason (process.env.MYVAR || '') does not help, as it evaluates to ('undefined' || '').",

The problem is that:\n\nconsole.log('xx' + process.env.MYVAR + 'xx');\n\n\nIs actually incorrect. The value of an undefined property is undefined. process.env.MYVAR = undefined is the same as delete process.env.MYVAR in so far as the value of the property is the same. But properties also have a presence that delete removes, in that the key will not show up in the Array returned by Object.keys.\n\nIf you want the empty string, instead you must write:\n\nconsole.log('xx' + (process.env.MYVAR || '') + 'xx');\n",

Make sure you understand that undefined !== \"\"\n\nUse this: process.env.MYVAR = \"\" if you want an empty string. undefined means there is nothing there. An empty string means there is the text of nothing to make it easy to understand.",