lasso/dist-compat/plugins/lasso-minify-js/index.js

Lasso.js is a build tool and runtime library for building and bundling all of the resources needed by a web application

var Terser = require('terser');
var codeFrame = require('babel-code-frame');
var internalOptions = ['inlineOnly'];
var hasOwn = Object.prototype.hasOwnProperty;

function minify(src, pluginOptions) {
    var minifyOptions = {};
    for (var key in pluginOptions) {
        if (hasOwn.call(pluginOptions, key) && internalOptions.indexOf(key) === -1) {
            minifyOptions[key] = pluginOptions[key];
        }
    }

    var result = Terser.minify(src, minifyOptions);

    if (result.error) {
        throw result.error;
    }

    return result.code;
}

function isInline(lassoContext) {
    if (lassoContext.inline === true) {
        return true;
    }

    if (lassoContext.dependency && lassoContext.dependency.inline === true) {
        return true;
    }

    return false;
}

module.exports = function (lasso, pluginConfig) {
    lasso.addTransform({
        contentType: 'js',

        name: module.id,

        stream: false,

        transform: function (code, lassoContext) {
            if (pluginConfig.inlineOnly === true && !isInline(lassoContext)) {
                // Skip minification when we are not minifying inline code
                return code;
            }

            try {
                var minified = minify(code, pluginConfig);
                if (minified.length && !minified.endsWith(';')) {
                    minified += ';';
                }
                return minified;
            } catch (e) {
                if (e.line) {
                    var dependency = lassoContext.dependency;
                    var frame = codeFrame(code, e.line, e.col, { highlightCode: true });
                    console.error(e.message + ' in ' + dependency + ' at line ' + e.line + ' column ' + e.col + ':\n' + frame);
                    return code;
                } else {
                    throw e;
                }
            }
        }
    });
};