@dnpr/cli
v2.0.0
Published
Build a command-line user interface with ease.
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2,612
Readme
cli
Build a command-line user interface with ease.
Installation
npm install @dnpr/cli
Usage
const { FlagTypes, parseArgv, parseFlagVal } = require("@dnpr/cli")
const { args, flags } = parseArgv(process.argv)
const boolean = parseFlagVal(flags, "-b", FlagTypes.boolean, true)
const number = parseFlagVal(flags, "-n", FlagTypes.number, 100)
const string = parseFlagVal(flags, "-s", FlagTypes.string, "hello")
const obj = parseFlagVal(flags, "-j", FlagTypes.json, { name: "dragonman225" })
API
This library interprets arguments with the following rules:
- An argument starting with "-" is a flag. It is a key-value pair in the form "-key=value". Note that when specifying a value, "=" cannot be omitted.
- An argument not starting with "-" is a normal argument. This library does not process it.
parseArgv(argv)
Parse an argument vector into flags and normal arguments.
argv
Type: string[]
@returns
{
flags: string[], // flags
args: string[] // normal arguments
}
parseFlagVal(flags, findPrefix, valType, defaultVal)
Parse a flag and return the parsed value in the specified type or return the default value.
flags
Type: string[]
findPrefix
Type: string
e.g. "-flag"
It can also be a regex, such as "(-f|--flag)".
valType
Type: string, must be one of "boolean", "number", "string", "json".
It is recommended to use the FlagTypes
constant as shown in Usage instead of directly specifying the strings.
Behavior of each valType
:
FlagTypes.boolean
— If the flag is found and it has a value, i.e. the "xxx" in "-bool=xxx", this function returns true only when the value is "true". If the flag is found but it has no value, this function returns true. Otherwise, this function returns defaultVal
.
FlagTypes.number
— If the flag has value, the value is parsed with Number()
, if the parsed value is Number.NaN
, this function returns defaultVal
, otherwise it returns the parsed number. If the flag has no value or it is not found, this function always returns defaultVal
.
FlagTypes.string
— If the flag has value, this function returns the value. Otherwise, it returns defaultVal
.
FlagTypes.json
— If the flag has value and the value can be parsed by JSON.parse()
, this function returns the value. Otherwise, it returns defaultVal
.
defaultVal
Type: any
The type of defaultVal
is not checked. The user must ensure that its type is consistent with the specified valType
.