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JavaScript

'use strict';
var fs = require('fs');
var assert = require('assert');
var Promise = require('promise');
var isPromise = require('is-promise');
var tr = (module.exports = function (transformer) {
return new Transformer(transformer);
});
tr.Transformer = Transformer;
tr.normalizeFn = normalizeFn;
tr.normalizeFnAsync = normalizeFnAsync;
tr.normalize = normalize;
tr.normalizeAsync = normalizeAsync;
tr.readFile = Promise.denodeify(fs.readFile);
tr.readFileSync = fs.readFileSync;
function normalizeFn(result) {
if (typeof result === 'function') {
return {fn: result, dependencies: []};
} else if (result && typeof result === 'object' && typeof result.fn === 'function') {
if ('dependencies' in result) {
if (!Array.isArray(result.dependencies)) {
throw new Error('Result should have a dependencies property that is an array');
}
} else {
result.dependencies = [];
}
return result;
} else {
throw new Error('Invalid result object from transform.');
}
}
function normalizeFnAsync(result, cb) {
return Promise.resolve(result).then(function (result) {
if (result && isPromise(result.fn)) {
return result.fn.then(function (fn) {
result.fn = fn;
return result;
});
}
return result;
}).then(tr.normalizeFn).nodeify(cb);
}
function normalize(result) {
if (typeof result === 'string') {
return {body: result, dependencies: []};
} else if (result && typeof result === 'object' && typeof result.body === 'string') {
if ('dependencies' in result) {
if (!Array.isArray(result.dependencies)) {
throw new Error('Result should have a dependencies property that is an array');
}
} else {
result.dependencies = [];
}
return result;
} else {
throw new Error('Invalid result object from transform.');
}
}
function normalizeAsync(result, cb) {
return Promise.resolve(result).then(function (result) {
if (result && isPromise(result.body)) {
return result.body.then(function (body) {
result.body = body;
return result;
});
}
return result;
}).then(tr.normalize).nodeify(cb);
}
function Transformer(tr) {
assert(tr, 'Transformer must be an object');
assert(typeof tr.name === 'string', 'Transformer must have a name');
assert(typeof tr.outputFormat === 'string', 'Transformer must have an output format');
assert([
'compile',
'compileAsync',
'compileFile',
'compileFileAsync',
'compileClient',
'compileClientAsync',
'compileFileClient',
'compileFileClientAsync',
'render',
'renderAsync',
'renderFile',
'renderFileAsync'
].some(function (method) {
return typeof tr[method] === 'function';
}), 'Transformer must implement at least one of the potential methods.');
this._tr = tr;
this.name = this._tr.name;
this.outputFormat = this._tr.outputFormat;
this.inputFormats = this._tr.inputFormats || [this.name];
}
var fallbacks = {
compile: ['compile'],
compileAsync: ['compileAsync', 'compile'],
compileFile: ['compileFile', 'compile'],
compileFileAsync: ['compileFileAsync', 'compileFile', 'compileAsync', 'compile'],
compileClient: ['compileClient'],
compileClientAsync: ['compileClientAsync', 'compileClient'],
compileFileClient: ['compileFileClient', 'compileClient'],
compileFileClientAsync: [
'compileFileClientAsync', 'compileFileClient', 'compileClientAsync', 'compileClient'
],
render: ['render', 'compile'],
renderAsync: ['renderAsync', 'render', 'compileAsync', 'compile'],
renderFile: ['renderFile', 'render', 'compileFile', 'compile'],
renderFileAsync: [
'renderFileAsync', 'renderFile', 'renderAsync', 'render',
'compileFileAsync', 'compileFile', 'compileAsync', 'compile'
]
};
Transformer.prototype._hasMethod = function (method) {
return typeof this._tr[method] === 'function';
};
Transformer.prototype.can = function (method) {
return fallbacks[method].some(function (method) {
return this._hasMethod(method);
}.bind(this));
};
/* COMPILE */
Transformer.prototype.compile = function (str, options) {
if (!this.can('compile')) {
if (this.can('compileAsync')) {
throw new Error('The Transform "' + this.name + '" does not support synchronous compilation');
} else if (this.can('compileFileAsync')) {
throw new Error('The Transform "' + this.name + '" does not support compiling plain strings');
} else {
throw new Error('The Transform "' + this.name + '" does not support compilation');
}
}
return tr.normalizeFn(this._tr.compile(str, options));
};
Transformer.prototype.compileAsync = function (str, options, cb) {
if (!this.can('compileAsync')) {
if (this.can('compileFileAsync')) {
return Promise.reject(new Error('The Transform "' + this.name + '" does not support compiling plain strings')).nodeify(cb);
} else {
return Promise.reject(new Error('The Transform "' + this.name + '" does not support compilation')).nodeify(cb);
}
}
if (this._hasMethod('compileAsync')) {
return tr.normalizeFnAsync(this._tr.compileAsync(str, options), cb);
} else {
return tr.normalizeFnAsync(this._tr.compile(str, options), cb);
}
};
Transformer.prototype.compileFile = function (filename, options) {
if (!this.can('compileFile')) {
if (this.can('compileFileAsync')) {
throw new Error('The Transform "' + this.name + '" does not support synchronous compilation');
} else {
throw new Error('The Transform "' + this.name + '" does not support compilation');
}
}
if (this._hasMethod('compileFile')) {
return tr.normalizeFn(this._tr.compileFile(filename, options));
} else {
return tr.normalizeFn(this._tr.compile(tr.readFileSync(filename, 'utf8'), options));
}
};
Transformer.prototype.compileFileAsync = function (filename, options, cb) {
if (!this.can('compileFileAsync')) {
return Promise.reject(new Error('The Transform "' + this.name + '" does not support compilation'));
}
if (this._hasMethod('compileFileAsync')) {
return tr.normalizeFnAsync(this._tr.compileFileAsync(filename, options), cb);
} else if (this._hasMethod('compileFile')) {
return tr.normalizeFnAsync(this._tr.compileFile(filename, options), cb);
} else {
return tr.normalizeFnAsync(tr.readFile(filename, 'utf8').then(function (str) {
if (this._hasMethod('compileAsync')) {
return this._tr.compileAsync(str, options);
} else {
return this._tr.compile(str, options);
}
}.bind(this)), cb);
}
};
/* COMPILE CLIENT */
Transformer.prototype.compileClient = function (str, options) {
if (!this.can('compileClient')) {
if (this.can('compileClientAsync')) {
throw new Error('The Transform "' + this.name + '" does not support compiling for the client synchronously.');
} else if (this.can('compileFileClientAsync')) {
throw new Error('The Transform "' + this.name + '" does not support compiling for the client from a string.');
} else {
throw new Error('The Transform "' + this.name + '" does not support compiling for the client');
}
}
return tr.normalize(this._tr.compileClient(str, options));
};
Transformer.prototype.compileClientAsync = function (str, options, cb) {
if (!this.can('compileClientAsync')) {
if (this.can('compileFileClientAsync')) {
return Promise.reject(new Error('The Transform "' + this.name + '" does not support compiling for the client from a string.')).nodeify(cb);
} else {
return Promise.reject(new Error('The Transform "' + this.name + '" does not support compiling for the client')).nodeify(cb);
}
}
if (this._hasMethod('compileClientAsync')) {
return tr.normalizeAsync(this._tr.compileClientAsync(str, options), cb);
} else {
return tr.normalizeAsync(this._tr.compileClient(str, options), cb);
}
};
Transformer.prototype.compileFileClient = function (filename, options) {
if (!this.can('compileFileClient')) {
if (this.can('compileFileClientAsync')) {
throw new Error('The Transform "' + this.name + '" does not support compiling for the client synchronously.');
} else {
throw new Error('The Transform "' + this.name + '" does not support compiling for the client');
}
}
if (this._hasMethod('compileFileClient')) {
return tr.normalize(this._tr.compileFileClient(filename, options));
} else {
return tr.normalize(this._tr.compileClient(tr.readFileSync(filename, 'utf8'), options));
}
};
Transformer.prototype.compileFileClientAsync = function (filename, options, cb) {
if (!this.can('compileFileClientAsync')) {
return Promise.reject(new Error('The Transform "' + this.name + '" does not support compiling for the client')).nodeify(cb)
}
if (this._hasMethod('compileFileClientAsync')) {
return tr.normalizeAsync(this._tr.compileFileClientAsync(filename, options), cb);
} else if (this._hasMethod('compileFileClient')) {
return tr.normalizeAsync(this._tr.compileFileClient(filename, options), cb);
} else {
return tr.normalizeAsync(tr.readFile(filename, 'utf8').then(function (str) {
if (this._hasMethod('compileClientAsync')) {
return this._tr.compileClientAsync(str, options);
} else {
return this._tr.compileClient(str, options);
}
}.bind(this)), cb);
}
};
/* RENDER */
Transformer.prototype.render = function (str, options, locals) {
if (!this.can('render')) {
if (this.can('renderAsync')) {
throw new Error('The Transform "' + this.name + '" does not support rendering synchronously.');
} else if (this.can('renderFileAsync')) {
throw new Error('The Transform "' + this.name + '" does not support rendering from a string.');
} else {
throw new Error('The Transform "' + this.name + '" does not support rendering');
}
}
if (this._hasMethod('render')) {
return tr.normalize(this._tr.render(str, options, locals));
} else {
var compiled = tr.normalizeFn(this._tr.compile(str, options));
var body = compiled.fn(options || locals);
if (typeof body !== 'string') {
throw new Error('The Transform "' + this.name + '" does not support rendering synchronously.');
}
return tr.normalize({body: body, dependencies: compiled.dependencies});
}
};
Transformer.prototype.renderAsync = function (str, options, locals, cb) {
if (typeof locals === 'function') {
cb = locals;
locals = options;
}
if (!this.can('renderAsync')) {
if (this.can('renderFileAsync')) {
return Promise.reject(new Error('The Transform "' + this.name + '" does not support rendering from a string.')).nodeify(cb);
} else {
return Promise.reject(new Error('The Transform "' + this.name + '" does not support rendering')).nodeify(cb);
}
}
if (this._hasMethod('renderAsync')) {
return tr.normalizeAsync(this._tr.renderAsync(str, options, locals), cb);
} else if (this._hasMethod('render')) {
return tr.normalizeAsync(this._tr.render(str, options, locals), cb);
} else {
return tr.normalizeAsync(this.compileAsync(str, options).then(function (compiled) {
return {body: compiled.fn(options || locals), dependencies: compiled.dependencies};
}), cb);
}
};
Transformer.prototype.renderFile = function (filename, options, locals) {
if (typeof this._tr.renderFile === 'function') {
return tr.normalize(this._tr.renderFile(filename, options, locals));
} else if (typeof this._tr.render === 'function') {
return tr.normalize(this._tr.render(tr.readFileSync(filename, 'utf8'), options, locals));
} else if (this._hasMethod('compile') || this._hasMethod('compileFile')) {
var compiled = this.compileFile(filename, options);
return tr.normalize({body: compiled.fn(options || locals), dependencies: compiled.dependencies});
} else {
return Promise.reject(new Error('This transform does not support synchronous rendering'));
}
};
Transformer.prototype.renderFileAsync = function (filename, options, locals, cb) {
if (typeof locals === 'function') {
cb = locals;
locals = options;
}
if (typeof this._tr.renderFileAsync === 'function') {
return tr.normalizeAsync(this._tr.renderFileAsync(filename, options, locals), cb);
} else if (typeof this._tr.renderFile === 'function') {
return tr.normalizeAsync(this._tr.renderFile(filename, options, locals), cb);
} else if (this._hasMethod('compile') || this._hasMethod('compileAsync')
|| this._hasMethod('compileFile') || this._hasMethod('compileFileAsync')) {
return tr.normalizeAsync(this.compileFileAsync(filename, options).then(function (compiled) {
return {body: compiled.fn(options || locals), dependencies: compiled.dependencies};
}), cb);
} else {
return tr.normalizeAsync(tr.readFile(filename, 'utf8').then(function (str) {
return this.renderAsync(str, options, locals);
}.bind(this)), cb);
}
};