How might I add support for defaults? (And env?) #82
Description
(This is a bring-your-own-feature experiment, not a prototype of parseArgs implementation.)
Default values is our current canonical example of something that might get added in the future. A complication for some uses of defaults is telling whether the option value came from the user or the defaults. Another feature is support for options coming from environment variables.
Can we add all three of those in user land now?
const { parseArgs } = require('@pkgjs/parseargs');
const options = {
str: { type: 'string', short: 's' },
env: { type: 'string', env: 'ENV', short: 'e' },
def: { type: 'string', default: 'DEFAULT',short: 'd' }
};
const result = parseArgs({ options });
result.valueOrigins = {};
Object.keys(result.values).forEach(optionName => {
result.valueOrigins[optionName] = 'cli';
});
Object.entries(options)
.filter(([optionName, detail]) => result.values[optionName] === undefined)
.forEach(([optionName, detail]) => {
if (detail.env && process.env[detail.env] !== undefined) {
result.values[optionName] = process.env[detail.env];
result.valueOrigins[optionName] = 'env';
} else if (detail.default !== undefined) {
result.values[optionName] = detail.default;
result.valueOrigins[optionName] = 'default';
}
});
console.log(result);% ENV=EEE node index.js --str SSS ppp
{
values: { str: 'SSS', env: 'EEE', def: 'DEFAULT' },
positionals: [ 'ppp' ],
valueOrigins: { str: 'cli', env: 'env', def: 'default' }
}