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help.js
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Tue, Mar 4, 07:14

help.js
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const { humanReadableArgName } = require('./argument.js');
/**
* TypeScript import types for JSDoc, used by Visual Studio Code IntelliSense and `npm run typescript-checkJS`
* https://www.typescriptlang.org/docs/handbook/jsdoc-supported-types.html#import-types
* @typedef { import("./argument.js").Argument } Argument
* @typedef { import("./command.js").Command } Command
* @typedef { import("./option.js").Option } Option
*/
// @ts-check
// Although this is a class, methods are static in style to allow override using subclass or just functions.
class Help {
constructor() {
this.helpWidth = undefined;
this.sortSubcommands = false;
this.sortOptions = false;
}
/**
* Get an array of the visible subcommands. Includes a placeholder for the implicit help command, if there is one.
*
* @param {Command} cmd
* @returns {Command[]}
*/
visibleCommands(cmd) {
const visibleCommands = cmd.commands.filter(cmd => !cmd._hidden);
if (cmd._hasImplicitHelpCommand()) {
// Create a command matching the implicit help command.
const [, helpName, helpArgs] = cmd._helpCommandnameAndArgs.match(/([^ ]+) *(.*)/);
const helpCommand = cmd.createCommand(helpName)
.helpOption(false);
helpCommand.description(cmd._helpCommandDescription);
if (helpArgs) helpCommand.arguments(helpArgs);
visibleCommands.push(helpCommand);
}
if (this.sortSubcommands) {
visibleCommands.sort((a, b) => {
// @ts-ignore: overloaded return type
return a.name().localeCompare(b.name());
});
}
return visibleCommands;
}
/**
* Get an array of the visible options. Includes a placeholder for the implicit help option, if there is one.
*
* @param {Command} cmd
* @returns {Option[]}
*/
visibleOptions(cmd) {
const visibleOptions = cmd.options.filter((option) => !option.hidden);
// Implicit help
const showShortHelpFlag = cmd._hasHelpOption && cmd._helpShortFlag && !cmd._findOption(cmd._helpShortFlag);
const showLongHelpFlag = cmd._hasHelpOption && !cmd._findOption(cmd._helpLongFlag);
if (showShortHelpFlag || showLongHelpFlag) {
let helpOption;
if (!showShortHelpFlag) {
helpOption = cmd.createOption(cmd._helpLongFlag, cmd._helpDescription);
} else if (!showLongHelpFlag) {
helpOption = cmd.createOption(cmd._helpShortFlag, cmd._helpDescription);
} else {
helpOption = cmd.createOption(cmd._helpFlags, cmd._helpDescription);
}
visibleOptions.push(helpOption);
}
if (this.sortOptions) {
const getSortKey = (option) => {
// WYSIWYG for order displayed in help with short before long, no special handling for negated.
return option.short ? option.short.replace(/^-/, '') : option.long.replace(/^--/, '');
};
visibleOptions.sort((a, b) => {
return getSortKey(a).localeCompare(getSortKey(b));
});
}
return visibleOptions;
}
/**
* Get an array of the arguments if any have a description.
*
* @param {Command} cmd
* @returns {Argument[]}
*/
visibleArguments(cmd) {
// Side effect! Apply the legacy descriptions before the arguments are displayed.
if (cmd._argsDescription) {
cmd._args.forEach(argument => {
argument.description = argument.description || cmd._argsDescription[argument.name()] || '';
});
}
// If there are any arguments with a description then return all the arguments.
if (cmd._args.find(argument => argument.description)) {
return cmd._args;
};
return [];
}
/**
* Get the command term to show in the list of subcommands.
*
* @param {Command} cmd
* @returns {string}
*/
subcommandTerm(cmd) {
// Legacy. Ignores custom usage string, and nested commands.
const args = cmd._args.map(arg => humanReadableArgName(arg)).join(' ');
return cmd._name +
(cmd._aliases[0] ? '|' + cmd._aliases[0] : '') +
(cmd.options.length ? ' [options]' : '') + // simplistic check for non-help option
(args ? ' ' + args : '');
}
/**
* Get the option term to show in the list of options.
*
* @param {Option} option
* @returns {string}
*/
optionTerm(option) {
return option.flags;
}
/**
* Get the argument term to show in the list of arguments.
*
* @param {Argument} argument
* @returns {string}
*/
argumentTerm(argument) {
return argument.name();
}
/**
* Get the longest command term length.
*
* @param {Command} cmd
* @param {Help} helper
* @returns {number}
*/
longestSubcommandTermLength(cmd, helper) {
return helper.visibleCommands(cmd).reduce((max, command) => {
return Math.max(max, helper.subcommandTerm(command).length);
}, 0);
};
/**
* Get the longest option term length.
*
* @param {Command} cmd
* @param {Help} helper
* @returns {number}
*/
longestOptionTermLength(cmd, helper) {
return helper.visibleOptions(cmd).reduce((max, option) => {
return Math.max(max, helper.optionTerm(option).length);
}, 0);
};
/**
* Get the longest argument term length.
*
* @param {Command} cmd
* @param {Help} helper
* @returns {number}
*/
longestArgumentTermLength(cmd, helper) {
return helper.visibleArguments(cmd).reduce((max, argument) => {
return Math.max(max, helper.argumentTerm(argument).length);
}, 0);
};
/**
* Get the command usage to be displayed at the top of the built-in help.
*
* @param {Command} cmd
* @returns {string}
*/
commandUsage(cmd) {
// Usage
let cmdName = cmd._name;
if (cmd._aliases[0]) {
cmdName = cmdName + '|' + cmd._aliases[0];
}
let parentCmdNames = '';
for (let parentCmd = cmd.parent; parentCmd; parentCmd = parentCmd.parent) {
parentCmdNames = parentCmd.name() + ' ' + parentCmdNames;
}
return parentCmdNames + cmdName + ' ' + cmd.usage();
}
/**
* Get the description for the command.
*
* @param {Command} cmd
* @returns {string}
*/
commandDescription(cmd) {
// @ts-ignore: overloaded return type
return cmd.description();
}
/**
* Get the command description to show in the list of subcommands.
*
* @param {Command} cmd
* @returns {string}
*/
subcommandDescription(cmd) {
// @ts-ignore: overloaded return type
return cmd.description();
}
/**
* Get the option description to show in the list of options.
*
* @param {Option} option
* @return {string}
*/
optionDescription(option) {
const extraInfo = [];
// Some of these do not make sense for negated boolean and suppress for backwards compatibility.
if (option.argChoices && !option.negate) {
extraInfo.push(
// use stringify to match the display of the default value
`choices: ${option.argChoices.map((choice) => JSON.stringify(choice)).join(', ')}`);
}
if (option.defaultValue !== undefined && !option.negate) {
extraInfo.push(`default: ${option.defaultValueDescription || JSON.stringify(option.defaultValue)}`);
}
if (option.envVar !== undefined) {
extraInfo.push(`env: ${option.envVar}`);
}
if (extraInfo.length > 0) {
return `${option.description} (${extraInfo.join(', ')})`;
}
return option.description;
};
/**
* Get the argument description to show in the list of arguments.
*
* @param {Argument} argument
* @return {string}
*/
argumentDescription(argument) {
const extraInfo = [];
if (argument.argChoices) {
extraInfo.push(
// use stringify to match the display of the default value
`choices: ${argument.argChoices.map((choice) => JSON.stringify(choice)).join(', ')}`);
}
if (argument.defaultValue !== undefined) {
extraInfo.push(`default: ${argument.defaultValueDescription || JSON.stringify(argument.defaultValue)}`);
}
if (extraInfo.length > 0) {
const extraDescripton = `(${extraInfo.join(', ')})`;
if (argument.description) {
return `${argument.description} ${extraDescripton}`;
}
return extraDescripton;
}
return argument.description;
}
/**
* Generate the built-in help text.
*
* @param {Command} cmd
* @param {Help} helper
* @returns {string}
*/
formatHelp(cmd, helper) {
const termWidth = helper.padWidth(cmd, helper);
const helpWidth = helper.helpWidth || 80;
const itemIndentWidth = 2;
const itemSeparatorWidth = 2; // between term and description
function formatItem(term, description) {
if (description) {
const fullText = `${term.padEnd(termWidth + itemSeparatorWidth)}${description}`;
return helper.wrap(fullText, helpWidth - itemIndentWidth, termWidth + itemSeparatorWidth);
}
return term;
};
function formatList(textArray) {
return textArray.join('\n').replace(/^/gm, ' '.repeat(itemIndentWidth));
}
// Usage
let output = [`Usage: ${helper.commandUsage(cmd)}`, ''];
// Description
const commandDescription = helper.commandDescription(cmd);
if (commandDescription.length > 0) {
output = output.concat([commandDescription, '']);
}
// Arguments
const argumentList = helper.visibleArguments(cmd).map((argument) => {
return formatItem(helper.argumentTerm(argument), helper.argumentDescription(argument));
});
if (argumentList.length > 0) {
output = output.concat(['Arguments:', formatList(argumentList), '']);
}
// Options
const optionList = helper.visibleOptions(cmd).map((option) => {
return formatItem(helper.optionTerm(option), helper.optionDescription(option));
});
if (optionList.length > 0) {
output = output.concat(['Options:', formatList(optionList), '']);
}
// Commands
const commandList = helper.visibleCommands(cmd).map((cmd) => {
return formatItem(helper.subcommandTerm(cmd), helper.subcommandDescription(cmd));
});
if (commandList.length > 0) {
output = output.concat(['Commands:', formatList(commandList), '']);
}
return output.join('\n');
}
/**
* Calculate the pad width from the maximum term length.
*
* @param {Command} cmd
* @param {Help} helper
* @returns {number}
*/
padWidth(cmd, helper) {
return Math.max(
helper.longestOptionTermLength(cmd, helper),
helper.longestSubcommandTermLength(cmd, helper),
helper.longestArgumentTermLength(cmd, helper)
);
};
/**
* Wrap the given string to width characters per line, with lines after the first indented.
* Do not wrap if insufficient room for wrapping (minColumnWidth), or string is manually formatted.
*
* @param {string} str
* @param {number} width
* @param {number} indent
* @param {number} [minColumnWidth=40]
* @return {string}
*
*/
wrap(str, width, indent, minColumnWidth = 40) {
// Detect manually wrapped and indented strings by searching for line breaks
// followed by multiple spaces/tabs.
if (str.match(/[\n]\s+/)) return str;
// Do not wrap if not enough room for a wrapped column of text (as could end up with a word per line).
const columnWidth = width - indent;
if (columnWidth < minColumnWidth) return str;
const leadingStr = str.substr(0, indent);
const columnText = str.substr(indent);
const indentString = ' '.repeat(indent);
const regex = new RegExp('.{1,' + (columnWidth - 1) + '}([\\s\u200B]|$)|[^\\s\u200B]+?([\\s\u200B]|$)', 'g');
const lines = columnText.match(regex) || [];
return leadingStr + lines.map((line, i) => {
if (line.slice(-1) === '\n') {
line = line.slice(0, line.length - 1);
}
return ((i > 0) ? indentString : '') + line.trimRight();
}).join('\n');
}
}
exports.Help = Help;

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