knex/lib/interface.js

const { isEmpty, map, clone, each } = require('lodash');
const Bluebird = require('bluebird');

module.exports = function(Target) {
  Target.prototype.toQuery = function(tz) {
    let data = this.toSQL(this._method, tz);
    if (!Array.isArray(data)) data = [data];
    return map(data, (statement) => {
      return this.client._formatQuery(statement.sql, statement.bindings, tz);
    }).join(';\n');
  };

  // Create a new instance of the `Runner`, passing in the current object.
  Target.prototype.then = function(/* onFulfilled, onRejected */) {
    let result = this.client.runner(this).run();

    if (this.client.config.asyncStackTraces) {
      result = result.catch((err) => {
        err.originalStack = err.stack;
        const firstLine = err.stack.split('\n')[0];
        this._asyncStack.unshift(firstLine);
        // put the fake more helpful "async" stack on the thrown error
        err.stack = this._asyncStack.join('\n');
        throw err;
      });
    }

    return Bluebird.resolve(result.then.apply(result, arguments));
  };

  // Add additional "options" to the builder. Typically used for client specific
  // items, like the `mysql` and `sqlite3` drivers.
  Target.prototype.options = function(opts) {
    this._options = this._options || [];
    this._options.push(clone(opts) || {});
    return this;
  };

  // Sets an explicit "connection" we wish to use for this query.
  Target.prototype.connection = function(connection) {
    this._connection = connection;
    return this;
  };

  // Set a debug flag for the current schema query stack.
  Target.prototype.debug = function(enabled) {
    this._debug = arguments.length ? enabled : true;
    return this;
  };

  // Set the transaction object for this query.
  Target.prototype.transacting = function(t) {
    if (t && t.client) {
      if (!t.client.transacting) {
        t.client.logger.warn(`Invalid transaction value: ${t.client}`);
      } else {
        this.client = t.client;
      }
    }
    if (isEmpty(t)) {
      this.client.logger.error(
        'Invalid value on transacting call, potential bug'
      );
      throw Error(
        'Invalid transacting value (null, undefined or empty object)'
      );
    }
    return this;
  };

  // Initializes a stream.
  Target.prototype.stream = function(options) {
    return this.client.runner(this).stream(options);
  };

  // Initialize a stream & pipe automatically.
  Target.prototype.pipe = function(writable, options) {
    return this.client.runner(this).pipe(
      writable,
      options
    );
  };

  // Creates a method which "coerces" to a promise, by calling a
  // "then" method on the current `Target`
  each(
    [
      'bind',
      'catch',
      'finally',
      'asCallback',
      'spread',
      'map',
      'reduce',
      'thenReturn',
      'return',
      'yield',
      'ensure',
      'reflect',
      'get',
      'mapSeries',
      'delay',
    ],
    function(method) {
      Target.prototype[method] = function() {
        const promise = this.then();
        return promise[method].apply(promise, arguments);
      };
    }
  );
};