snip-text/lib/snip.js

Snip and extract parts from text content. Useful for generating code examples from unit tests.

"use strict";
var snipRegEx = /^\W*-{3,}\s*snip/;
var snippetRegEx = /^\W*-{3,}\s*snippet:?\s*([^-]*)\s*/i;
function defaultMatcher(line) {
    var snippetMatch = snippetRegEx.exec(line);
    if (snippetMatch)
        return typeof snippetMatch[1] === "string" ? snippetMatch[1].trim() : true;
    var snipMatch = snipRegEx.exec(line);
    if (snipMatch)
        return true;
    return false;
}
var spaceRegEx = /^\s+/;
var tabRegEx = /^\t+/;
var nonspaceRegEx = /\S/;
function snip(contents, options) {
    options = options || {};
    options.joiner = options.joiner || "\n";
    options.matcher = options.matcher || defaultMatcher;
    options.tabSize = options.tabSize || 4;
    var tabStr = options.unindent ? "\t" : makeSpace(options.tabSize);
    var lines = contents.split(/\r?\n/);
    var snipping = false;
    var snippets = {};
    var snippet;
    lines.forEach(function (line) {
        var match = options.matcher(line);
        if (match) {
            if (typeof match === "string") {
                snippet = snippets[match] || (snippets[match] = { lines: [] });
                snipping = true;
            }
            else if (!snipping) {
                if (!snippet)
                    snippet = snippets[" "] = { lines: [] };
                snipping = true;
            }
            else
                snipping = false;
        }
        else if (snipping && snippet) {
            if (options.unindent && nonspaceRegEx.test(line)) {
                var tabs = tabRegEx.exec(line);
                if (tabs)
                    line = makeSpace(tabs[0].length * options.tabSize) + line.substr(tabs[0].length);
                if (snippet.indent !== 0) {
                    var indent = spaceRegEx.exec(line);
                    if (indent) {
                        if (snippet.indent === undefined || indent[0].length < snippet.indent)
                            snippet.indent = indent[0].length;
                    }
                    else {
                        snippet.indent = 0;
                    }
                }
            }
            snippet.lines.push(line);
        }
    });
    if (options.unindent) {
        Object.getOwnPropertyNames(snippets).forEach(function (key) {
            var snippet = snippets[key];
            if (snippet.indent) {
                for (var i = 0; i < snippet.lines.length; i++)
                    snippet.lines[i] = snippet.lines[i].substr(snippet.indent);
            }
        });
    }
    var result = {};
    Object.keys(snippets).forEach(function (key) {
        result[key] = snippets[key].lines.join(options.joiner);
    });
    return result;
}
exports.snip = snip;
function makeSpace(n) {
    var res = "";
    while (n) {
        res += " ";
        n--;
    }
    return res;
}